Your Local Water Profile: Mission Viejo
This profile explains what the applicable water provider reported for Mission Viejo, what those results may mean throughout a home, and where property-specific testing or inspection may still be needed.
First, confirm your water provider.
Water service can vary by address. Confirm the provider shown on your water bill before applying provider-specific results.
What the official water report says
Your water at a glance
Santa Margarita Water District
The report lists hardness as 256 ppm; this is very hard on the USGS scale.
USGS hardness scale: 0–60 soft; 61–120 moderately hard; 121–180 hard; >180 very hard, in mg/L as CaCO3.
Moulton Niguel Water District
The report lists hardness as 270 ppm; this is very hard on the USGS scale.
USGS hardness scale: 0–60 soft; 61–120 moderately hard; 121–180 hard; >180 very hard, in mg/L as CaCO3.
El Toro Water District
The report lists hardness as 270 ppm; this is very hard on the USGS scale.
Reported range: 235 - 305 ppm
USGS hardness scale: 0–60 soft; 61–120 moderately hard; 121–180 hard; >180 very hard, in mg/L as CaCO3.
Santa Margarita Water District — compliance, as reported
The report states: “Santa Margarita Water District (SMWD) vigilantly safeguards its water supply, and as in years past, the water delivered to your home meets or surpasses the quality standards required by federal and state regulatory agencies. [p. 2]”
Violations or advisories, as reported: On January 21, 2025, a higher than normal (7 NTU) grab sample result was reported at the IRWD Baker Water Treatment Plant. This value is inconsistent with the continuous online analyzer which showed a reading of 0.0259 NTU at the same time that the grab sample was taken. The available evidence suggests that the higher than normal grab sample was not a valid representation of the water quality produced by the plant at the time. No other result above 0.1 NTU was reported throughout the year.
Moulton Niguel Water District — compliance, as reported
The report states: “Moulton Niguel’s water is safe and continues to meet all state and federal water quality standards.”
Violations or advisories, as reported: No violations occurred. The report states: \"Moulton Niguel’s water is safe and continues to meet all state and federal water quality standards.\" There were zero detections for all 29 PFAS chemicals tested.
El Toro Water District — compliance, as reported
The report states: “the water delivered to your home meets or exceeds the quality standards required by federal and state regulatory agencies.”
Violations or advisories, as reported: No violations were reported. The water delivered meets or exceeds the quality standards required by federal and state regulatory agencies.
Trabuco Canyon Water District — compliance, as reported
No overall compliance statement was extracted from the reviewed report.
The Three C's — 1 of 3
Chemistry
What does this water tend to do in a home?
Santa Margarita Water District
Hardness, total as CaCO3
The utility reported: 256 ppm
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Hardness, total
The utility reported: 15 grains/gallon
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
pH
The utility reported: 7.59 pH units
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Total Dissolved Solids
The utility reported: 614 ppm
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Alkalinity, total as CaCO3
The utility reported: 113 ppm
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Sodium
The utility reported: 95 ppm
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Copper
The utility reported: 0.079 ppm
LEAD AND COPPER ACTION LEVELS AT RESIDENTIAL TAPS · report p. 5 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit ppb
LEAD AND COPPER ACTION LEVELS AT RESIDENTIAL TAPS · report p. 5 · official report
Chlorine Residual
The utility reported: 1.83 ppm
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Hardness, total as CaCO3
The utility reported: 293 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Hardness, total
The utility reported: 17 grains/gallon
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Calcium
The utility reported: 73 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Magnesium
The utility reported: 26.9 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
pH
The utility reported: 7.6 pH units
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Alkalinity, total as CaCO3
The utility reported: 119 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Total Dissolved Solids
The utility reported: 625 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Chloride
The utility reported: 109 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Sulfate
The utility reported: 219 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Sodium
The utility reported: 101 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Hardness, total as CaCO3
The utility reported: 236 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Hardness, total
The utility reported: 14 grains/gal
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Calcium
The utility reported: 56 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Magnesium
The utility reported: 22 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
pH
The utility reported: 8.3 pH units
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Alkalinity, total as CaCO3
The utility reported: 108 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Total Dissolved Solids
The utility reported: 545 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Chloride
The utility reported: 92 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Sulfate
The utility reported: 182 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Sodium
The utility reported: 88 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Moulton Niguel Water District
Hardness, total as CaCO3
The utility reported: 270 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Hardness, total
The utility reported: 15.7 grains/gallon
Diemer Water Treatment Plant · report p. PAGE 11 · official report
pH
The utility reported: 8.2 pH units
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Alkalinity, total as CaCO3
The utility reported: 114 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Total Dissolved Solids
The utility reported: 621 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Sodium
The utility reported: 103 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Chloride
The utility reported: 104 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Sulfate
The utility reported: 224 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Specific Conductance
The utility reported: 979 μmho/cm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Calcium
The utility reported: 68 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Magnesium
The utility reported: 26 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Color
The utility reported: 2 color units
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Odor
The utility reported: 1 threshold odor number
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Turbidity
The utility reported: 0.06 NTU
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Hardness, total as CaCO3
The utility reported: 295 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Hardness as Grains per Gallon
The utility reported: 17.21 grains/gallon
Baker Water Treatment Plant · report p. PAGE 12 · official report
pH
The utility reported: 7.9 pH units
Baker Water Treatment Plant · report p. PAGE 12 · official report
Alkalinity, total as CaCO3
The utility reported: 124 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Total Dissolved Solids
The utility reported: 642 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Sodium
The utility reported: 105 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Chloride
The utility reported: 112 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Sulfate
The utility reported: 237 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Specific Conductance
The utility reported: 1,065 μmho/cm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Calcium
The utility reported: 72.7 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Magnesium
The utility reported: 27.9 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Color
The utility reported: <3 color units
Baker Water Treatment Plant · report p. PAGE 12 · official report
Odor
The utility reported: 1.8 threshold odor number
Baker Water Treatment Plant · report p. PAGE 12 · official report
Turbidity
The utility reported: 0.04 NTU
Baker Water Treatment Plant · report p. PAGE 12 · official report
El Toro Water District
Alkalinity, total as CaCO3
The utility reported: 114 ppm
Reported range: 105 - 123
MWDSC · report p. PAGE 5 · official report
Hardness, total as CaCO3
The utility reported: 270 ppm
Reported range: 235 - 305
MWDSC · report p. PAGE 5 · official report
Sodium
The utility reported: 103 ppm
Reported range: 90 - 116
MWDSC · report p. PAGE 5 · official report
Chloride
The utility reported: 104 ppm
Reported range: 93 - 116
MWDSC · report p. PAGE 5 · official report
Sulfate
The utility reported: 224 ppm
Reported range: 196 - 253
MWDSC · report p. PAGE 5 · official report
Specific Conductance
The utility reported: 979 \u00b5mho/cm
Reported range: 888 - 1,070
MWDSC · report p. PAGE 5 · official report
Total Dissolved Solids
The utility reported: 621 ppm
Reported range: 556 - 686
MWDSC · report p. PAGE 5 · official report
Calcium
The utility reported: 68 ppm
Reported range: 58 - 78
MWDSC · report p. PAGE 5 · official report
Magnesium
The utility reported: 26 ppm
Reported range: 22 - 29
MWDSC · report p. PAGE 5 · official report
Color
The utility reported: 2 color units
Reported range: 1-2
MWDSC · report p. PAGE 5 · official report
Odor
The utility reported: 1 threshold odor number
Reported range: 1
MWDSC · report p. PAGE 5 · official report
Turbidity
The utility reported: 0.06 ntu
Reported range: ND - 0.22
ETWD Distribution · report p. PAGE 7 · official report
Alkalinity, total as CaCO3
The utility reported: 124 ppm
Reported range: 115 - 144
IRWD · report p. PAGE 6 · official report
Hardness, total as CaCO3
The utility reported: 295 ppm
Reported range: 281 - 313
IRWD · report p. PAGE 6 · official report
pH
The utility reported: 7.9 pH unit
Reported range: 7.4 - 8.6
IRWD · report p. PAGE 6 · official report
Sodium
The utility reported: 105 ppm
Reported range: 90.3 - 114
IRWD · report p. PAGE 6 · official report
Chloride
The utility reported: 112 ppm
Reported range: 98.4 - 119
IRWD · report p. PAGE 6 · official report
Sulfate
The utility reported: 237 ppm
Reported range: 228 - 243
IRWD · report p. PAGE 6 · official report
Specific Conductance
The utility reported: 1,065 \u00b5mho/cm
Reported range: 1,008 - 1,126
IRWD · report p. PAGE 6 · official report
Total Dissolved Solids
The utility reported: 642 ppm
Reported range: 588 - 712
IRWD · report p. PAGE 6 · official report
Calcium
The utility reported: 72.7 ppm
Reported range: 67.2 - 79.5
IRWD · report p. PAGE 6 · official report
Magnesium
The utility reported: 27.9 ppm
Reported range: 26.2 - 29.8
IRWD · report p. PAGE 6 · official report
Color
The utility reported: Not detected at the report's stated reporting limit color units
Reported range: ND - 8
IRWD · report p. PAGE 6 · official report
Odor
The utility reported: 2 threshold odor number
Reported range: ND - 4
IRWD · report p. PAGE 6 · official report
Trabuco Canyon Water District
General mineral and treatment characteristics were not itemized in this provider's reviewed report. The official report link in the Sources section below is the authoritative record.
The Three C's — 2 of 3
Contaminants
What was reported, and what do the applicable standards mean?
Legal limit — maximum contaminant level (MCL)
The highest level legally allowed in public drinking water under the applicable rule. Do not use MCL as a generic label for goals, action levels, notification levels, or independent guidelines. It is different from a non-enforceable health goal.
California health goal — public health goal (PHG)
A non-enforceable health-protective target developed for standard-setting context. It is not the California legal limit.
Federal health goal — maximum contaminant level goal (MCLG)
A non-enforceable EPA public-health target used in setting standards. It is not the legal limit.
Legal disinfectant-residual limit — maximum residual disinfectant level (MRDL)
The highest level of a drinking-water disinfectant allowed under the applicable rule. It is not an MCL for a contaminant.
Santa Margarita Water District — regulated contaminants reported as detected (18)
Chlorine Residual
The utility reported: 1.83 ppm
Reported range: 1.61 - 1.99
MRDL: 4 · Health goal (MRDLG): 4 — not an enforceable limit
Violation per report: No
Typical source, per the report: Disinfectant Added for Treatment
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Haloacetic Acids
The utility reported: 8 ppb
Reported range: 4.1 - 10
Legal limit (MCL): 60
Violation per report: No
Typical source, per the report: Byproducts of Chlorine Disinfection
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Total Trihalomethanes
The utility reported: 32 ppb
Reported range: 20 - 37
Legal limit (MCL): 80
Violation per report: No
Typical source, per the report: Byproducts of Chlorine Disinfection
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Copper
The utility reported: 0.079 ppm
Reported range: ND - 0.16
AL: 1.3 · Health goal (PHG): 0.3 — not an enforceable limit
Violation per report: No
Typical source, per the report: Corrosion of Household Plumbing
LEAD AND COPPER ACTION LEVELS AT RESIDENTIAL TAPS · report p. 5 · official report
Uranium
The utility reported: 1.9 pCi/L
Reported range: 1.9
Legal limit (MCL): 20 · Health goal (PHG): 0.43 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of Natural Deposits
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Barium
The utility reported: 0.129 ppm
Reported range: 0.119 - 0.141
Legal limit (MCL): 1 · Health goal (PHG): 2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Refinery Discharge, Erosion of Natural Deposits
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Fluoride
The utility reported: 0.33 ppm
Reported range: 0.27 - 0.37
Legal limit (MCL): 2.0 · Health goal (PHG): 1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of Natural Deposits; Water Additive for Dental Health
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Total Organic Carbon
The utility reported: 2.9 ppm
Reported range: 2.9
TT: TT
Violation per report: N/A
Typical source, per the report: Various Natural and Man-made Sources
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Turbidity - combined filter effluent (Highest single measurement)
The utility reported: 0.030 NTU
TT: 0.1
Violation per report: No
Typical source, per the report: Soil Runoff
IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Turbidity - combined filter effluent (Percentage <= 0.3 NTU)
The utility reported: 100% %
TT: 95%
Violation per report: No
Typical source, per the report: Soil Runoff
IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Uranium
The utility reported: 1 pCi/L
Reported range: ND - 3
Legal limit (MCL): 20 · Health goal (PHG): 0.43 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of Natural Deposits
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Aluminum
The utility reported: 0.058 ppm
Reported range: ND - 0.082
Legal limit (MCL): 1 · Health goal (PHG): 0.6 — not an enforceable limit
Violation per report: No
Typical source, per the report: Treatment Process Residue, Natural Deposits
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Barium
The utility reported: 0.13 ppm
Reported range: 0.13
Legal limit (MCL): 1 · Health goal (PHG): 2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Refinery Discharge, Erosion of Natural Deposits
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Bromate
The utility reported: 2.4 ppb
Reported range: ND - 8.4
Legal limit (MCL): 10 · Health goal (PHG): 0.1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Byproduct of Drinking Water Ozonation
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Fluoride
The utility reported: 0.7 ppm
Reported range: 0.6 - 0.8
Legal limit (MCL): 2 · Health goal (PHG): 1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Water Additive for Dental Health
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Total Organic Carbon
The utility reported: 2.4 ppm
Reported range: 1.6 - 2.6
TT: TT
Violation per report: N/A
Typical source, per the report: Various Natural and Man-made Sources
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Turbidity - combined filter effluent (Highest single measurement)
The utility reported: 0.05 NTU
TT: 0.3
Violation per report: No
Typical source, per the report: Soil Runoff
METROPOLITAN WATER DISTRICT DIEMER FILTRATION PLANT · report p. 7 · official report
Turbidity - combined filter effluent (Percentage <= 0.3 NTU)
The utility reported: 100% %
TT: 95%
Violation per report: No
Typical source, per the report: Soil Runoff
METROPOLITAN WATER DISTRICT DIEMER FILTRATION PLANT · report p. 7 · official report
Santa Margarita Water District — unregulated monitoring and secondary (aesthetic) records (17)
Unregulated means monitored without an applicable enforceable legal limit (MCL) — it does not mean unimportant or illegal. Secondary records address aesthetic, cosmetic, or technical effects such as taste, odor, staining, or scale, and are not automatically primary health standards.
Color
The utility reported: 1 color units
Reported range: 1
Typical source, per the report: Erosion of Natural Deposits
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Odor
The utility reported: 1 threshold odor number
Reported range: 1
Typical source, per the report: Erosion of Natural Deposits
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Specific Conductance
The utility reported: 926 µmho/cm
Reported range: 445 - 1,102
Typical source, per the report: Erosion of Natural Deposits
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Turbidity
The utility reported: 0.07 NTU
Reported range: 0.01 - 0.50
Typical source, per the report: Erosion of Natural Deposits
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Odor
The utility reported: 1 threshold odor number
Reported range: ND - 3
Typical source, per the report: Naturally-occurring Organic Materials
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Specific Conductance
The utility reported: 1,049 µmho/cm
Reported range: 1,030 - 1,068
Typical source, per the report: Substances that Form Ions in Water
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Turbidity
The utility reported: 0.25 NTU
Reported range: ND - 7
Typical source, per the report: Soil Runoff
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Boron
The utility reported: 0.143 ppm
Reported range: 0.13 - 0.186
Typical source, per the report: Runoff or Leaching from Natural Deposits
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Lithium
The utility reported: 65.7 ppb
Reported range: 64.2 - 67.2
Typical source, per the report: Various Natural and Man-made Sources
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Potassium
The utility reported: 5.4 ppm
Reported range: 4.9 - 6
Typical source, per the report: Runoff or Leaching from Natural Deposits
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Lithium
The utility reported: 38 ppb
Reported range: 30 - 47
UNREGULATED CHEMICALS REQUIRING MONITORING · report p. 6 · official report
Aluminum
The utility reported: 58 ppb
Reported range: ND - 82
Typical source, per the report: Treatment Process Residue, Natural Deposits
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Color
The utility reported: 1 color units
Reported range: 1
Typical source, per the report: Naturally-occurring Organic Materials
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Specific Conductance
The utility reported: 873 µmho/cm
Reported range: 759 - 987
Typical source, per the report: Substances that Form Ions in Water
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Boron
The utility reported: 0.13 ppm
Reported range: 0.13
Typical source, per the report: Runoff or Leaching from Natural Deposits
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Potassium
The utility reported: 4.3 ppm
Reported range: 3.8 - 4.8
Typical source, per the report: Runoff or Leaching from Natural Deposits
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Lithium
The utility reported: 38 ppb
Reported range: 30 - 47
UNREGULATED CHEMICALS REQUIRING MONITORING · report p. 7 · official report
Moulton Niguel Water District — regulated contaminants reported as detected (21)
Gross Alpha Particle Activity
The utility reported: Not detected at the report's stated reporting limit pCi/L
Reported range: ND - 5
Benchmark: 15 · Health goal (goal): (0) — not an enforceable limit
Violation per report: No
Typical source, per the report: Runoff leaching of natural deposits
Reported constituent · report p. PAGE 11 · official report
Gross Beta Particle Activity
The utility reported: 4 pCi/L
Reported range: ND - 5
Benchmark: 50 · Health goal (goal): (0) — not an enforceable limit
Violation per report: No
Typical source, per the report: Decay of natural and man-made deposits
Reported constituent · report p. PAGE 11 · official report
Uranium
The utility reported: 1 pCi/L
Reported range: ND - 3
Benchmark: 20 · Health goal (goal): 0.43 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits
Reported constituent · report p. PAGE 11 · official report
Aluminum
The utility reported: Not detected at the report's stated reporting limit ppm
Reported range: ND - 0.11
Benchmark: 1 · Health goal (goal): 0.6 — not an enforceable limit
Violation per report: No
Typical source, per the report: Treatment Process Residue, Natural Deposits
Reported constituent · report p. PAGE 11 · official report
Barium
The utility reported: 0.12 ppm
Reported range: 0.12
Benchmark: 1 · Health goal (goal): 2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Runoff and leaching from fertilizer use, septic tanks and sewage; natural deposits erosion
Reported constituent · report p. PAGE 11 · official report
Fluoride
The utility reported: 0.7 ppm
Reported range: 0.6 - 0.8
Benchmark: 2 · Health goal (goal): 1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Water Additive for Dental Health. Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 11 · official report
Bromate
The utility reported: Not detected at the report's stated reporting limit ppb
Reported range: ND - 1.6
Benchmark: 10 · Health goal (goal): 0.1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Byproduct of drinking water ozonation
Reported constituent · report p. PAGE 11 · official report
Total Organic Carbon
The utility reported: 2.4 ppm
Reported range: 2.0 - 2.5
Benchmark: TT
Violation per report: No
Typical source, per the report: Various Natural and Man-made Sources. TOC is a precursor for the formation of disinfection byproducts
Reported constituent · report p. PAGE 11 · official report
Total Trihalomethanes
The utility reported: 52 ppb
Reported range: 23.5 - 49.6
Benchmark: 80
Reported constituent · report p. PAGE 11 · official report
Haloacetic Acids
The utility reported: 24 ppb
Reported range: 6.4 - 32.7
Benchmark: 60
Reported constituent · report p. PAGE 11 · official report
Disinfectant Residual (chloramines)
The utility reported: 2.17 mg/L
Reported range: 0.8 - 3.0
Benchmark: 4
Reported constituent · report p. PAGE 11 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit ppb
Benchmark: 15
Reported constituent · report p. PAGE 11 · official report
Copper
The utility reported: 0.103 mg/L
Benchmark: 1.3
Reported constituent · report p. PAGE 11 · official report
Gross Alpha Particle Activity
The utility reported: 3.8 pCi/L
Reported range: 3.8
Benchmark: 15 · Health goal (goal): (0) — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits
Reported constituent · report p. PAGE 12 · official report
Gross Beta Particle Activity
The utility reported: 4.6 pCi/L
Reported range: 4.6
Benchmark: 50 · Health goal (goal): (0) — not an enforceable limit
Violation per report: No
Typical source, per the report: Decay of natural and man-made deposits
Reported constituent · report p. PAGE 12 · official report
Uranium
The utility reported: 2.2 pCi/L
Reported range: 2.2
Benchmark: 20 · Health goal (goal): 0.43 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits
Reported constituent · report p. PAGE 12 · official report
Arsenic
The utility reported: 1.9 ppb
Reported range: 1.54 - 2.27
Benchmark: 10 · Health goal (goal): 0.004 — not an enforceable limit
Violation per report: No
Typical source, per the report: Treatment Process Residue, Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Barium
The utility reported: 0.129 ppm
Reported range: 0.11 - 0.14
Benchmark: 1 · Health goal (goal): 2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Oil and metal refineries discharge; Natural deposits erosion
Reported constituent · report p. PAGE 12 · official report
Fluoride
The utility reported: 0.35 ppm
Reported range: 0.31 - 0.38
Benchmark: 2 · Health goal (goal): 1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits; water additive that promotes strong teeth
Reported constituent · report p. PAGE 12 · official report
Chlorite
The utility reported: Not detected at the report's stated reporting limit ppm
Reported range: ND - 0.09
Benchmark: 1 · Health goal (goal): 0.05 — not an enforceable limit
Violation per report: No
Typical source, per the report: Byproduct of drinking water chlorination
Reported constituent · report p. PAGE 12 · official report
Chlorine Dioxide
The utility reported: 98.5 ppb
Reported range: ND - 680
Benchmark: MRDL = 800 · Health goal (goal): MRDLG = 800 — not an enforceable limit
Violation per report: No
Typical source, per the report: Drinking water disinfectant added for treatment
Reported constituent · report p. PAGE 12 · official report
Moulton Niguel Water District — unregulated monitoring and secondary (aesthetic) records (40)
Unregulated means monitored without an applicable enforceable legal limit (MCL) — it does not mean unimportant or illegal. Secondary records address aesthetic, cosmetic, or technical effects such as taste, odor, staining, or scale, and are not automatically primary health standards.
Aluminum
The utility reported: Not detected at the report's stated reporting limit ppb
Reported range: ND - 110
Typical source, per the report: Treatment Process Residue, Natural Deposits
Reported constituent · report p. PAGE 11 · official report
Chloride
The utility reported: 104 ppm
Reported range: 93 - 116
Typical source, per the report: Runoff or Leaching from Natural Deposits; seawater influence
Reported constituent · report p. PAGE 11 · official report
Color
The utility reported: 2 color units
Reported range: 1-2
Typical source, per the report: Naturally-occurring Organic Materials
Reported constituent · report p. PAGE 11 · official report
Odor
The utility reported: 1 threshold odor number
Reported range: 1
Typical source, per the report: Naturally-occurring Organic Materials
Reported constituent · report p. PAGE 11 · official report
Specific Conductance
The utility reported: 979 μmho/cm
Reported range: 888 - 1,070
Typical source, per the report: Substances that form ions in Water; seawater influence
Reported constituent · report p. PAGE 11 · official report
Sulfate
The utility reported: 224 ppm
Reported range: 196 - 253
Typical source, per the report: Runoff or Leaching from Natural Deposits; industrial wastes
Reported constituent · report p. PAGE 11 · official report
Total Dissolved Solids
The utility reported: 621 ppm
Reported range: 556 - 686
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 11 · official report
Chlorate
The utility reported: 77 ppb
Reported range: 77
Typical source, per the report: Byproduct of drinking water chlorination; industrial process
Reported constituent · report p. PAGE 11 · official report
Boron
The utility reported: 0.14 ppm
Reported range: 0.14
Typical source, per the report: Runoff or Leaching from Natural Deposits; industrial wastes
Reported constituent · report p. PAGE 11 · official report
Hardness, total as CaCO3
The utility reported: 270 ppm
Reported range: 235 - 305
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 11 · official report
Hardness, total
The utility reported: 15.7 grains/gallon
Reported range: 13.7 - 17.8
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 11 · official report
Magnesium
The utility reported: 26 ppm
Reported range: 22 - 29
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 11 · official report
pH
The utility reported: 8.2 pH units
Reported range: 8.2
Typical source, per the report: Hydrogen Ion Concentration
Reported constituent · report p. PAGE 11 · official report
Potassium
The utility reported: 4.9 ppm
Reported range: 4.4 - 5.4
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 11 · official report
N-Nitrosodi-n-butylamine
The utility reported: 2.5 ppt
Reported range: 2.5
Typical source, per the report: Byproduct of drinking water chloramination; industrial processes
Reported constituent · report p. PAGE 11 · official report
Sodium
The utility reported: 103 ppm
Reported range: 90 - 116
Typical source, per the report: Salt present in water; naturally-occurring
Reported constituent · report p. PAGE 11 · official report
Alkalinity, total as CaCO3
The utility reported: 114 ppm
Reported range: 105 - 123
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 11 · official report
Calcium
The utility reported: 68 ppm
Reported range: 58 - 78
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 11 · official report
Chloride
The utility reported: 112 ppm
Reported range: 98.4 - 119
Typical source, per the report: Runoff or Leaching from Natural Deposits; sea water influence
Reported constituent · report p. PAGE 12 · official report
Color
The utility reported: <3 color units
Reported range: <3 - 8
Typical source, per the report: Naturally-occurring Organic Materials
Reported constituent · report p. PAGE 12 · official report
Manganese
The utility reported: 1.44 ppb
Reported range: ND - 47
Typical source, per the report: Leaching from natural deposits
Reported constituent · report p. PAGE 12 · official report
Odor
The utility reported: 1.8 threshold odor number
Reported range: <1 - 4
Typical source, per the report: Naturally-occurring Organic Materials
Reported constituent · report p. PAGE 12 · official report
Specific Conductance
The utility reported: 1,065 μmho/cm
Reported range: 1008 - 1126
Typical source, per the report: Substances that form ions in Water; sea water influence
Reported constituent · report p. PAGE 12 · official report
Sulfate
The utility reported: 237 ppm
Reported range: 228 - 243
Typical source, per the report: Runoff or Leaching from Natural Deposits; industrial wastes
Reported constituent · report p. PAGE 12 · official report
Total Dissolved Solids
The utility reported: 642 ppm
Reported range: 588 - 712
Typical source, per the report: Runoff or Leaching from Natural Deposits; sea water influence
Reported constituent · report p. PAGE 12 · official report
Alkalinity, total as CaCO3
The utility reported: 124 ppm
Reported range: 115 - 144
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Bicarbonate
The utility reported: 124 ppb
Reported range: 115 - 144
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Boron
The utility reported: 0.13 ppm
Reported range: 0.12 - 0.15
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Carbonate
The utility reported: <0.6 ppm
Reported range: <0.6 - 0.87
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Calcium
The utility reported: 72.7 ppm
Reported range: 67.2 - 79.5
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Hardness, total as CaCO3
The utility reported: 295 ppm
Reported range: 281 - 313
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Hardness as Grains per Gallon
The utility reported: 17.21 grains/gallon
Reported range: 16.39 - 18.26
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Magnesium
The utility reported: 27.9 ppm
Reported range: 26.2 - 29.8
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Molybdenum
The utility reported: 5.4 ppb
Reported range: 4.83 - 5.74
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
pH
The utility reported: 7.9 pH units
Reported range: 7.4 - 8.6
Typical source, per the report: Hydrogen Ion Concentration
Reported constituent · report p. PAGE 12 · official report
Potassium
The utility reported: 5.96 ppm
Reported range: 4.83 - 21.2
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Sodium
The utility reported: 105 ppm
Reported range: 90.3 - 114
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 12 · official report
Vanadium
The utility reported: 2.4 ppb
Reported range: 2.08 - 2.73
Typical source, per the report: Naturally occurring; industrial waste discharge
Reported constituent · report p. PAGE 12 · official report
Total Organic Carbon
The utility reported: 1.9 ppm
Reported range: 1.9
Typical source, per the report: Various natural and man-made sources
Reported constituent · report p. PAGE 12 · official report
Lithium
The utility reported: 33.8 ppb
Reported range: 9.4 - 43.0
Reported constituent · report p. PAGE 13 · official report
El Toro Water District — regulated contaminants reported as detected (20)
Gross Alpha Particle Activity
The utility reported: Not detected at the report's stated reporting limit pCi/L
Reported range: ND - 5
Benchmark: 15 · Health goal (goal): 0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Gross Beta Particle Activity
The utility reported: 4 pCi/L
Reported range: ND - 5
Benchmark: 50 · Health goal (goal): 0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Decay of Natural and Man-made Deposits
Reported constituent · report p. PAGE 5 · official report
Uranium
The utility reported: 1 pCi/L
Reported range: ND - 3
Benchmark: 20 · Health goal (goal): 0.43 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Aluminum
The utility reported: Not detected at the report's stated reporting limit ppm
Reported range: ND - 0.11
Benchmark: 1 · Health goal (goal): 0.6 — not an enforceable limit
Violation per report: No
Typical source, per the report: Treatment Process Residue, Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Barium
The utility reported: 0.124 ppm
Reported range: 0.124
Benchmark: 1 · Health goal (goal): 2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Refinery Discharge, Erosion of Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Bromate
The utility reported: Not detected at the report's stated reporting limit ppb
Reported range: ND - 1.6
Benchmark: 10 · Health goal (goal): 0.1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Byproduct of Drinking Water Ozonation
Reported constituent · report p. PAGE 5 · official report
Fluoride
The utility reported: 0.7 ppm
Reported range: 0.6 - 0.8
Benchmark: 2 · Health goal (goal): 1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Water Additive for Dental Health
Reported constituent · report p. PAGE 5 · official report
Gross Alpha Particle Activity
The utility reported: 3.8 pCi/L
Reported range: 3.8
Benchmark: 15 · Health goal (goal): 0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Gross Beta Particle Activity
The utility reported: 4.6 pCi/L
Reported range: 4.6
Benchmark: 50 · Health goal (goal): 0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Decay of Natural and Man-made Deposits
Reported constituent · report p. PAGE 6 · official report
Uranium
The utility reported: 2.2 pCi/L
Reported range: 2.2
Benchmark: 20 · Health goal (goal): 0.43 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Arsenic
The utility reported: 2 ppb
Reported range: 2 - 2.27
Benchmark: 10 · Health goal (goal): 0.004 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Barium
The utility reported: 0.129 ppm
Reported range: 0.113 - 0.141
Benchmark: 1 · Health goal (goal): 2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Refinery Discharge, Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Chlorine Dioxide
The utility reported: 98.5 ppb
Reported range: ND - 680
Benchmark: 800 · Health goal (goal): 800 — not an enforceable limit
Violation per report: No
Typical source, per the report: Drinking Water Disinfectant Added for Treatment
Reported constituent · report p. PAGE 6 · official report
Chlorite
The utility reported: Not detected at the report's stated reporting limit ppm
Reported range: ND - 0.09
Benchmark: 1.0 · Health goal (goal): 0.05 — not an enforceable limit
Violation per report: No
Typical source, per the report: Byproduct of Drinking Water Chlorination
Reported constituent · report p. PAGE 6 · official report
Fluoride
The utility reported: 0.35 ppm
Reported range: 0.31 - 0.38
Benchmark: 2.0 · Health goal (goal): 1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of Natural Deposits; Water Additive for Dental Health
Reported constituent · report p. PAGE 6 · official report
Total Trihalomethanes
The utility reported: 56 ppb
Reported range: 23 - 56
Benchmark: 80
Violation per report: No
Typical source, per the report: Byproducts of Chlorine Disinfection
Reported constituent · report p. PAGE 7 · official report
Haloacetic Acids
The utility reported: 20 ppb
Reported range: 6.0 - 33
Benchmark: 60
Violation per report: No
Typical source, per the report: Byproducts of Chlorine Disinfection
Reported constituent · report p. PAGE 7 · official report
Chlorine Residual
The utility reported: 1.68 ppm
Reported range: 0.3 - 3.78
Benchmark: 4 · Health goal (goal): 4 — not an enforceable limit
Violation per report: No
Typical source, per the report: Disinfectant Added for Treatment
Reported constituent · report p. PAGE 7 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit ppb
Reported range: ND
Benchmark: 15 · Health goal (goal): 0.2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Corrosion of Household Plumbing
Reported constituent · report p. PAGE 7 · official report
Copper
The utility reported: 0.082 ppm
Reported range: 0.082
Benchmark: 1.3 · Health goal (goal): 0.3 — not an enforceable limit
Violation per report: No
Typical source, per the report: Corrosion of Household Plumbing
Reported constituent · report p. PAGE 7 · official report
El Toro Water District — unregulated monitoring and secondary (aesthetic) records (37)
Unregulated means monitored without an applicable enforceable legal limit (MCL) — it does not mean unimportant or illegal. Secondary records address aesthetic, cosmetic, or technical effects such as taste, odor, staining, or scale, and are not automatically primary health standards.
Aluminum
The utility reported: Not detected at the report's stated reporting limit ppb
Reported range: ND - 110
Typical source, per the report: Treatment Process Residue, Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Chloride
The utility reported: 104 ppm
Reported range: 93 - 116
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Color
The utility reported: 2 color units
Reported range: 1-2
Typical source, per the report: Naturally-occurring Organic Materials
Reported constituent · report p. PAGE 5 · official report
Odor
The utility reported: 1 threshold odor number
Reported range: 1
Typical source, per the report: Naturally-occurring Organic Materials
Reported constituent · report p. PAGE 5 · official report
Specific Conductance
The utility reported: 979 \u00b5mho/cm
Reported range: 888 - 1,070
Typical source, per the report: Substances that Form Ions in Water
Reported constituent · report p. PAGE 5 · official report
Sulfate
The utility reported: 224 ppm
Reported range: 196 - 253
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Total Dissolved Solids
The utility reported: 621 ppm
Reported range: 556 - 686
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Alkalinity, total as CaCO3
The utility reported: 114 ppm
Reported range: 105 - 123
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Boron
The utility reported: 0.14 ppm
Reported range: 0.14
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Calcium
The utility reported: 68 ppm
Reported range: 58 - 78
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Hardness, total as CaCO3
The utility reported: 270 ppm
Reported range: 235 - 305
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Hardness, total
The utility reported: 16 grains/gal
Reported range: 14 - 18
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Magnesium
The utility reported: 26 ppm
Reported range: 22 - 29
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
pH
The utility reported: 8.2 units
Reported range: 8.2
Typical source, per the report: Hydrogen Ion Concentration
Reported constituent · report p. PAGE 5 · official report
Potassium
The utility reported: 4.9 ppm
Reported range: 4.4 - 5.4
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Sodium
The utility reported: 103 ppm
Reported range: 90 - 116
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Total Organic Carbon
The utility reported: 2.4 ppm
Reported range: 2 - 2.5
Typical source, per the report: Various Natural and Man-made Sources
Reported constituent · report p. PAGE 5 · official report
Lithium
The utility reported: 45 ppb
Reported range: 44 - 45
Reported constituent · report p. PAGE 5 · official report
Chloride
The utility reported: 112 ppm
Reported range: 98.4 - 119
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Color
The utility reported: Not detected at the report's stated reporting limit color units
Reported range: ND - 8
Typical source, per the report: Naturally-occurring Organic Materials
Reported constituent · report p. PAGE 6 · official report
Manganese
The utility reported: 1.44 ppb
Reported range: ND - 47
Typical source, per the report: Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Odor
The utility reported: 2 threshold odor number
Reported range: ND - 4
Typical source, per the report: Naturally-occurring Organic Materials
Reported constituent · report p. PAGE 6 · official report
Specific Conductance
The utility reported: 1,065 \u00b5mho/cm
Reported range: 1,008 - 1,126
Typical source, per the report: Substances that Form Ions in Water
Reported constituent · report p. PAGE 6 · official report
Sulfate
The utility reported: 237 ppm
Reported range: 228 - 243
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Total Dissolved Solids
The utility reported: 642 ppm
Reported range: 588 - 712
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Turbidity
The utility reported: Not detected at the report's stated reporting limit ntu
Reported range: ND - 0.3
Typical source, per the report: Soil Runoff
Reported constituent · report p. PAGE 6 · official report
Alkalinity, total as CaCO3
The utility reported: 124 ppm
Reported range: 115 - 144
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Boron
The utility reported: 0.138 ppm
Reported range: 0.127 - 0.153
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Calcium
The utility reported: 72.7 ppm
Reported range: 67.2 - 79.5
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Hardness, total as CaCO3
The utility reported: 295 ppm
Reported range: 281 - 313
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Hardness, total
The utility reported: 17 grains per gallon
Reported range: 16 - 18
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Magnesium
The utility reported: 27.9 ppm
Reported range: 26.2 - 29.8
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
pH
The utility reported: 7.9 pH unit
Reported range: 7.4 - 8.6
Typical source, per the report: Hydrogen Ion Concentration
Reported constituent · report p. PAGE 6 · official report
Potassium
The utility reported: 5.9 ppm
Reported range: 4.83 - 21.2
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Sodium
The utility reported: 105 ppm
Reported range: 90.3 - 114
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Total Organic Carbon
The utility reported: 1.9 ppm
Reported range: 1.9
Typical source, per the report: Various Natural and Man-made Sources
Reported constituent · report p. PAGE 6 · official report
Turbidity
The utility reported: 0.06 ntu
Reported range: ND - 0.22
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 7 · official report
Trabuco Canyon Water District — regulated contaminants reported as detected (0)
No itemized regulated-detection records were extracted from this provider's reviewed report. That is a limit of the extraction, not a claim that nothing was detected — the official report linked below is authoritative.
The Three C's — 3 of 3
Corrosion
What conditions could influence pipes, fixtures, and a water heater?
Santa Margarita Water District
pH
The utility reported: 7.59 pH units
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Alkalinity, total as CaCO3
The utility reported: 113 ppm
2025 SANTA MARGARITA WATER DISTRICT DISTRIBUTION SYSTEM WATER QUALITY · report p. 5 · official report
Copper
The utility reported: 0.079 ppm
LEAD AND COPPER ACTION LEVELS AT RESIDENTIAL TAPS · report p. 5 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit ppb
LEAD AND COPPER ACTION LEVELS AT RESIDENTIAL TAPS · report p. 5 · official report
pH
The utility reported: 7.6 pH units
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Alkalinity, total as CaCO3
The utility reported: 119 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Chloride
The utility reported: 109 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
Sulfate
The utility reported: 219 ppm
2025 IRVINE RANCH WATER DISTRICT BAKER WATER TREATMENT PLANT · report p. 6 · official report
pH
The utility reported: 8.3 pH units
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Alkalinity, total as CaCO3
The utility reported: 108 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Chloride
The utility reported: 92 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Sulfate
The utility reported: 182 ppm
2025 METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA TREATED SURFACE WATER · report p. 7 · official report
Moulton Niguel Water District
pH
The utility reported: 8.2 pH units
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Alkalinity, total as CaCO3
The utility reported: 114 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Chloride
The utility reported: 104 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
Sulfate
The utility reported: 224 ppm
Diemer Water Treatment Plant · report p. PAGE 11 · official report
pH
The utility reported: 7.9 pH units
Baker Water Treatment Plant · report p. PAGE 12 · official report
Alkalinity, total as CaCO3
The utility reported: 124 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Chloride
The utility reported: 112 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Sulfate
The utility reported: 237 ppm
Baker Water Treatment Plant · report p. PAGE 12 · official report
Gross Alpha Particle Activity
The utility reported: Not detected at the report's stated reporting limit pCi/L
Reported range: ND - 5
Typical source, per the report: Runoff leaching of natural deposits
Reported constituent · report p. PAGE 11 · official report
Disinfectant Residual (chloramines)
The utility reported: 2.17 mg/L
Reported range: 0.8 - 3.0
Reported constituent · report p. PAGE 11 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit ppb
Reported constituent · report p. PAGE 11 · official report
Gross Alpha Particle Activity
The utility reported: 3.8 pCi/L
Reported range: 3.8
Typical source, per the report: Erosion of natural deposits
Reported constituent · report p. PAGE 12 · official report
El Toro Water District
Alkalinity, total as CaCO3
The utility reported: 114 ppm
Reported range: 105 - 123
MWDSC · report p. PAGE 5 · official report
Chloride
The utility reported: 104 ppm
Reported range: 93 - 116
MWDSC · report p. PAGE 5 · official report
Sulfate
The utility reported: 224 ppm
Reported range: 196 - 253
MWDSC · report p. PAGE 5 · official report
Alkalinity, total as CaCO3
The utility reported: 124 ppm
Reported range: 115 - 144
IRWD · report p. PAGE 6 · official report
pH
The utility reported: 7.9 pH unit
Reported range: 7.4 - 8.6
IRWD · report p. PAGE 6 · official report
Chloride
The utility reported: 112 ppm
Reported range: 98.4 - 119
IRWD · report p. PAGE 6 · official report
Sulfate
The utility reported: 237 ppm
Reported range: 228 - 243
IRWD · report p. PAGE 6 · official report
Gross Alpha Particle Activity
The utility reported: Not detected at the report's stated reporting limit pCi/L
Reported range: ND - 5
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 5 · official report
Gross Alpha Particle Activity
The utility reported: 3.8 pCi/L
Reported range: 3.8
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit ppb
Reported range: ND
Typical source, per the report: Corrosion of Household Plumbing
Reported constituent · report p. PAGE 7 · official report
Copper
The utility reported: 0.082 ppm
Reported range: 0.082
Typical source, per the report: Corrosion of Household Plumbing
Reported constituent · report p. PAGE 7 · official report
Trabuco Canyon Water District
Corrosion-related inputs (such as pH or alkalinity) were not itemized in this provider's reviewed report.
Whole-Home Relevance
What this may mean throughout your home
Local conditions can be relevant to equipment and fixtures — actual effects depend on your property.
Water heater (tank and tankless)
- What the local report can tell us
- The report's hardness and mineral values above are the system-level inputs most relevant to scale and sediment where water is heated.
- What a homeowner may notice
- Hardness minerals can contribute to scale on heating surfaces, sediment in tanks, and more frequent flushing or descaling needs.
- What the report cannot tell us
- Property-specific outcomes — actual effects depend on temperature, use, equipment design, installation, maintenance, and property plumbing.
- Responsible next step
- Inspect the actual water heater and plumbing when symptoms involve hot-water odor, scale, sediment, corrosion, flow, noise, or repeated service demand.
Dishwasher and washing machine
- What the local report can tell us
- Reported hardness and secondary (aesthetic) records are the relevant system-level context for spotting and residue.
- What a homeowner may notice
- Hard water can change soap behavior and may contribute to spotting on dishes and residue in laundry.
- What the report cannot tell us
- Property-specific outcomes — actual effects depend on temperature, use, equipment design, installation, maintenance, and property plumbing.
- Responsible next step
- Inspect the actual water heater and plumbing when symptoms involve hot-water odor, scale, sediment, corrosion, flow, noise, or repeated service demand.
Pipes, fixtures, faucets, and supply lines
- What the local report can tell us
- The corrosion-related inputs above (such as pH) describe the water entering the property — not the condition of any specific plumbing.
- What a homeowner may notice
- Mineral deposits can appear on aerators and fixtures; corrosion outcomes depend on materials, age, and water conditions together.
- What the report cannot tell us
- Property-specific outcomes — actual effects depend on temperature, use, equipment design, installation, maintenance, and property plumbing.
- Responsible next step
- Inspect the actual water heater and plumbing when symptoms involve hot-water odor, scale, sediment, corrosion, flow, noise, or repeated service demand.
Drinking and cooking water
- What the local report can tell us
- The contaminant records above show what the utility reported for the system and period, with each benchmark type labeled.
- What a homeowner may notice
- Taste, odor, or aesthetic preferences can be noticeable even when health-based standards are met.
- What the report cannot tell us
- Property-specific outcomes — actual effects depend on temperature, use, equipment design, installation, maintenance, and property plumbing.
- Responsible next step
- Inspect the actual water heater and plumbing when symptoms involve hot-water odor, scale, sediment, corrosion, flow, noise, or repeated service demand.
Decision Pathways
Treatment pathways to evaluate
Treatment is a decision pathway, not a product conclusion — no equipment can be responsibly chosen from city-level data alone.
The evaluation sequence we follow, in order:
- 1Define the concern
- 2Verify utility-level and home-specific evidence
- 3Choose point of treatment
- 4Verify the exact certified reduction claim for the exact model
- 5Review tradeoffs and maintenance
Water filtration
- Objective it can address
- Specific substances or aesthetic conditions (taste, odor, chlorine character).
- Point of treatment
- Point of entry or point of use, depending on the objective.
- Limitations to verify
- A filter works only for the conditions and reduction claims its exact design and certification support — filtration does not soften water.
Certification note: a standard number alone doesn't prove a product reduces every contaminant — the exact model's certified claim must match your objective.
Water softening
- Objective it can address
- Hardness minerals (calcium and magnesium) and the scale they can contribute to.
- Point of treatment
- Typically point of entry, confirmed by evaluation.
- Limitations to verify
- Softening primarily exchanges hardness minerals — it is not a universal contaminant-removal device.
Certification note: a standard number alone doesn't prove a product reduces every contaminant — the exact model's certified claim must match your objective.
Reverse osmosis
- Objective it can address
- Specified dissolved substances at a dedicated outlet, commonly drinking and cooking water.
- Point of treatment
- Typically point of use.
- Limitations to verify
- Produces a reject-water stream and needs pressure and maintenance; verify the exact NSF/ANSI 58 reduction claims for the exact model. It is not automatically the best system for every home.
Certification note: a standard number alone doesn't prove a product reduces every contaminant — the exact model's certified claim must match your objective.
When testing is the right next step
Use a certified laboratory when the concern is tap-specific, property-specific, or not resolved by the utility report.
When inspection is the right next step
Inspect the actual water heater and plumbing when symptoms involve hot-water odor, scale, sediment, corrosion, flow, noise, or repeated service demand.
Evidence You Can Check
Official reports, sources, and methodology
Official report — Santa Margarita Water District
Your 2026 Water Quality Report · data year 2025 · Current 2025 monitoring cycle
View the 2025 Santa Margarita Water District Consumer Confidence ReportSource water, per the report: Your drinking water consists of imported treated surface water from MWDSC and treated surface water from IRWD’s Baker Water Treatment Plant, which uses surface water from both MWDSC and Santiago Reservoir (Irvine Lake). MWDSC’s imported water sources are the Colorado River and the State Water Project, which draws water from the Sacramento–San Joaquin River Delta.
Official report — Moulton Niguel Water District
2024 Water Quality Report · data year 2024 · 2024 data retained; monitor for the next official update
View the 2024 Moulton Niguel Water District Consumer Confidence ReportSource water, per the report: Moulton Niguel relies on imported water from MWD, which sources its water supply from the Colorado River and the State Water Project. The water is treated at the Diemer Water Treatment Plant in Yorba Linda and the Baker Water Treatment Plant in Lake Forest. The Baker Water Treatment Plant also receives untreated surface water from Irvine Lake (Santiago Reservoir).
Official report — El Toro Water District
2025 DRINKING WATER QUALITY REPORT · data year 2024 · 2024 data retained; monitor for the next official update
View the 2024 El Toro Water District Consumer Confidence ReportSource water, per the report: Drinking water consists of imported treated surface water from MWDSC and treated surface water from IRWD's Baker Water Treatment Plant, which treats surface water from MWDSC and the Santiago Reservoir (Irvine Lake). MWDSC's imported water sources are the Colorado River and the State Water Project, which draws water from the Sacramento-San Joaquin River Delta.
Official report — Trabuco Canyon Water District
Consumer Confidence Report Certification Form · data year 2025 · Current 2025 monitoring cycle
View the 2025 Trabuco Canyon Water District Consumer Confidence ReportNearby community water profiles
Property-Specific Next Step
Request a Water Quality Evaluation
Request a water-heater and water-quality evaluation tailored to the property, equipment, and homeowner objective.
A property-specific evaluation confirms your goals, provider, tap conditions, plumbing, equipment, installation, and maintenance before any treatment recommendation — this profile alone is never used to prescribe equipment.
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