Your Local Water Profile: Costa Mesa
This profile explains what the applicable water provider reported for Costa Mesa, what those results may mean throughout a home, and where property-specific testing or inspection may still be needed.
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What the official water report says
Your water at a glance
Mesa Water District
The report lists hardness as 109 ppm as CaCO3; this is not classified because the reported unit could not be normalized 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.
Irvine Ranch Water District
The report lists hardness as 295 ppm as CaCO3; this is not classified because the reported unit could not be normalized 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.
Mesa Water District — compliance, as reported
The report states: “Mesa Water conducts more than 30,000 water quality tests annually to ensure our water meets or surpasses all state and federal drinking water regulations.”
Violations or advisories, as reported: No violations were reported. All regulated contaminants were within acceptable limits. Lead was detected in two samples, with one exceeding the action level, but the re-sample was ND and the 90th percentile was well below the regulatory action level, requiring no further action.
Irvine Ranch Water District — compliance, as reported
The report states: “In 2024, IRWD drinking water met or exceeded all state and federal standards. [p. 2]”
The Three C's — 1 of 3
Chemistry
What does this water tend to do in a home?
Mesa Water District
Specific Conductance
The utility reported: 542 μmho/cm
Groundwater · report p. PAGE 6 · official report
Alkalinity, total
The utility reported: 143 ppm as CaCO3
Groundwater · report p. PAGE 6 · official report
Hardness, total
The utility reported: 109 ppm as CaCO3
Groundwater · report p. PAGE 6 · official report
Color
The utility reported: Not detected at the report's stated reporting limit color units
Groundwater · report p. PAGE 6 · official report
Odor
The utility reported: Not detected at the report's stated reporting limit threshold odor number
Groundwater · report p. PAGE 6 · official report
Odor
The utility reported: 1 threshold odor number
Treated Surface Water · report p. PAGE 7 · official report
Specific Conductance
The utility reported: 979 μmho/cm
Treated Surface Water · report p. PAGE 7 · official report
Total Dissolved Solids
The utility reported: 621 ppm
Treated Surface Water · report p. PAGE 7 · official report
Alkalinity, total
The utility reported: 114 ppm as CaCO3
Treated Surface Water · report p. PAGE 7 · official report
Hardness, total
The utility reported: 270 ppm as CaCO3
Treated Surface Water · report p. PAGE 7 · official report
Turbidity - Combined filter effluent
The utility reported: 0.06 NTU
Treated Surface Water · report p. PAGE 7 · official report
Irvine Ranch Water District
Hardness, total
The utility reported: 295 ppm as CaCO3
Unregulated contaminants · report p. 8 · official report
Hardness, total
The utility reported: 17.3 grains/gal
Unregulated contaminants · report p. 8 · official report
Alkalinity, total
The utility reported: 124 ppm as CaCO3
Unregulated contaminants · report p. 8 · official report
Total Dissolved Solids
The utility reported: 642 ppm
Secondary standards · report p. 8 · official report
Lead
The utility reported: <5 ppb
Lead and copper action levels at residential taps · report p. 7 · official report
Copper
The utility reported: 0.1908 ppm
Lead and copper action levels at residential taps · report p. 7 · official report
Chlorine residual
The utility reported: 1.9 ppm
Disinfection byproducts · report p. 7 · official report
Corrosivity (Aggressiveness)
The utility reported: 12.5
Unregulated contaminants · report p. 8 · official report
Corrosivity (Langlier Index)
The utility reported: 0.62
Unregulated contaminants · report p. 8 · official report
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.
Mesa 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 - 3.77
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
Combined Radium
The utility reported: Not detected at the report's stated reporting limit pCi/L
Reported range: ND - 1.38
Benchmark: 5 · 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
Uranium
The utility reported: Not detected at the report's stated reporting limit pCi/L
Reported range: ND - 2.83
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: Not detected at the report's stated reporting limit ppb
Reported range: ND - 3
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
Fluoride
The utility reported: 0.46 ppm
Reported range: 0.27 - 0.80
Benchmark: 2 · Health goal (goal): 1 — 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
Hexavalent Chromium
The utility reported: 0.34 ppb
Reported range: ND - 0.80
Benchmark: 10 · Health goal (goal): 0.02 — 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
Nitrate
The utility reported: 0.42 ppm as N
Reported range: ND - 1.55
Benchmark: 10 · Health goal (goal): 10 — not an enforceable limit
Violation per report: No
Typical source, per the report: Fertilizers, Septic Tanks
Reported constituent · report p. PAGE 6 · official report
Nitrate+Nitrite
The utility reported: 0.42 ppm as N
Reported range: ND - 1.55
Benchmark: 10 · Health goal (goal): 10 — not an enforceable limit
Violation per report: No
Typical source, per the report: Fertilizers, Septic Tanks
Reported constituent · report p. PAGE 6 · official report
Total Trihalomethanes
The utility reported: 19 ppb
Reported range: ND - 30
Benchmark: 80
Violation per report: No
Typical source, per the report: Byproducts of Chlorine Disinfection
Reported constituent · report p. PAGE 6 · official report
Haloacetic Acids
The utility reported: 3 ppb
Reported range: ND - 4
Benchmark: 60
Violation per report: No
Typical source, per the report: Byproducts of Chlorine Disinfection
Reported constituent · report p. PAGE 6 · official report
Chlorine Residual
The utility reported: 2.11 ppm
Reported range: 0.10 - 2.94
Benchmark: (4 / 4)
Violation per report: No
Typical source, per the report: Disinfectant Added for Treatment
Reported constituent · report p. PAGE 6 · official report
Copper
The utility reported: 0.087 ppm
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 6 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit ppb
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 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
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 7 · 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 7 · 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 7 · official report
Aluminum
The utility reported: Not detected at the report's stated reporting limit ppm
Reported range: ND - 0.15
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 7 · 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 7 · official report
Bromate
The utility reported: Not detected at the report's stated reporting limit ppb
Reported range: ND - 9.2
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 7 · official report
Fluoride
The utility reported: 0.7 ppm
Reported range: 0.3 - 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 7 · official report
Mesa 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.
Color
The utility reported: Not detected at the report's stated reporting limit color units
Reported range: ND - 5
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Chloride
The utility reported: 56 ppm
Reported range: 12 - 147
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Odor
The utility reported: Not detected at the report's stated reporting limit threshold odor number
Reported range: ND - 4
Typical source, per the report: Naturally-Occuring Organic Materials
Reported constituent · report p. PAGE 6 · official report
Specific Conductance
The utility reported: 542 μmho/cm
Reported range: 210 - 919
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Sulfate
The utility reported: 43 ppm
Reported range: 1.4 - 112
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Total Dissolved Solids
The utility reported: 319 ppm
Reported range: 126 - 496
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Alkalinity, total
The utility reported: 143 ppm as CaCO3
Reported range: 79.4 - 201
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Bicarbonate
The utility reported: 163 ppm as HCO3
Reported range: 97 - 219
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Boron
The utility reported: 0.2 ppm
Reported range: ND - 0.51
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Calcium
The utility reported: 33 ppm
Reported range: 7.6 - 70
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
1,4-Dioxane
The utility reported: 1.1 ppb
Reported range: ND - 4.2
Typical source, per the report: Treated Wastewater
Reported constituent · report p. PAGE 6 · official report
Hardness, total
The utility reported: 109 ppm as CaCO3
Reported range: 21.3 - 237
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Hardness, total
The utility reported: 6.4 grains/gal
Reported range: 1.2 - 14
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Magnesium
The utility reported: 6.4 ppm
Reported range: ND - 15
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
N-Nitrosodimethylamine (NDMA)
The utility reported: Not detected at the report's stated reporting limit ppt
Reported range: ND
Typical source, per the report: Treated Wastewater
Reported constituent · report p. PAGE 6 · official report
pH
The utility reported: 8.2 units
Reported range: 7.9 - 8.8
Typical source, per the report: Acidity, Hydrogen Ions
Reported constituent · report p. PAGE 6 · official report
Potassium
The utility reported: 1.6 ppm
Reported range: 0.8 - 2.4
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Sodium
The utility reported: 70.9 ppm
Reported range: 21.5 - 170
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Vanadium
The utility reported: 4.5 ppb
Reported range: ND - 7
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Color
The utility reported: 1 color units
Reported range: ND - 5
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Turbidity
The utility reported: 0.09 NTU
Reported range: ND - 0.54
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Aluminum
The utility reported: Not detected at the report's stated reporting limit ppb
Reported range: ND - 150
Typical source, per the report: Treatment Process Residue, Natural Deposits
Reported constituent · report p. PAGE 7 · 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 7 · official report
Color
The utility reported: 2 color units
Reported range: 1-2
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 7 · official report
Odor
The utility reported: 1 threshold odor number
Reported range: ND - 1
Typical source, per the report: Naturally-occurring Organic Materials
Reported constituent · report p. PAGE 7 · official report
Specific Conductance
The utility reported: 979 μmho/cm
Reported range: 888 - 1,080
Typical source, per the report: Substances that Form Ions in Water
Reported constituent · report p. PAGE 7 · 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 7 · official report
Total Dissolved Solids
The utility reported: 621 ppm
Reported range: 556 - 690
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 7 · official report
Alkalinity, total
The utility reported: 114 ppm as CaCO3
Reported range: 105 - 127
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 7 · 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 7 · 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 7 · official report
Chlorate
The utility reported: 77 ppb
Reported range: 77 - 80
Typical source, per the report: Byproduct of Drinking Water Chlorination
Reported constituent · report p. PAGE 7 · official report
Hardness, total
The utility reported: 270 ppm as CaCO3
Reported range: 235 - 305
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 7 · 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 7 · 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 7 · 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 7 · 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 7 · official report
Sodium
The utility reported: 103 ppm
Reported range: 90 - 117
Typical source, per the report: Runoff or Leaching from Natural Deposits
Reported constituent · report p. PAGE 7 · official report
Total Organic Carbon
The utility reported: 2.4 ppm
Reported range: 2 - 2.6
Typical source, per the report: Various Natural and Man-made Sources
Reported constituent · report p. PAGE 7 · official report
Lithium
The utility reported: 22 ppb
Reported range: ND - 37
Reported constituent · report p. PAGE 7 · official report
Irvine Ranch Water District — regulated contaminants reported as detected (22)
Total Trihalomethanes
The utility reported: 24.1 ppb
Reported range: 9.1 - 44.2
Legal limit (MCL): 80
Violation per report: No
Typical source, per the report: Byproducts of chlorine disinfection
Disinfection byproducts · report p. 7 · official report
Haloacetic Acids (five)
The utility reported: 10.0 ppb
Reported range: 4.1 - 19.6
Legal limit (MCL): 60
Violation per report: No
Typical source, per the report: Byproducts of chlorine disinfection
Disinfection byproducts · report p. 7 · official report
Chlorine residual
The utility reported: 1.9 ppm
Reported range: ND - 3.9
MRDL: 4.0 · Health goal (MRDLG): 4 — not an enforceable limit
Violation per report: No
Typical source, per the report: Disinfectant added for treatment
Disinfection byproducts · report p. 7 · official report
Color
The utility reported: <3 color units
Reported range: ND - 4
Legal limit (MCL): 15
Violation per report: No
Typical source, per the report: Erosion of natural deposits
Aesthetic quality · report p. 7 · official report
Turbidity
The utility reported: 0.1 NTU
Reported range: ND - 6.9
Legal limit (MCL): 5
Violation per report: No
Typical source, per the report: Erosion of natural deposits
Aesthetic quality · report p. 7 · official report
Odor
The utility reported: <1 threshold odor number
Reported range: ND - 4
Legal limit (MCL): 3
Violation per report: No
Typical source, per the report: Erosion of natural deposits
Aesthetic quality · report p. 7 · official report
Fluoride
The utility reported: 0.54 mg/L
Reported range: 0.18 - 0.80
Legal limit (MCL): 2 · Health goal (MCLG): 0.8 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits, water treatment
Other · report p. 7 · official report
Copper
The utility reported: 0.1908 ppm
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. 7 · official report
Lead
The utility reported: <5 ppb
AL: 15 · Health goal (PHG): 0.2 — 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. 7 · official report
Alpha Radiation
The utility reported: 1.9 pCi/L
Reported range: ND - 3.8
Legal limit (MCL): 15 · Health goal (PHG): 0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits
Radiologicals · report p. 8 · official report
Beta Radiation
The utility reported: 4.6 pCi/L
Reported range: ND - 5.0
Legal limit (MCL): 50 · Health goal (PHG): 0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Decay of natural and man-made deposits
Radiologicals · report p. 8 · official report
Uranium
The utility reported: 2.2 pCi/L
Reported range: ND - 3.0
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
Radiologicals · report p. 8 · official report
Aluminum
The utility reported: 0.105 ppm
Reported range: ND - 0.110
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
Inorganic chemicals · report p. 8 · official report
Arsenic
The utility reported: 2.00 ppb
Reported range: ND - 3.04
Legal limit (MCL): 10 · Health goal (PHG): 0.004 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits
Inorganic chemicals · report p. 8 · official report
Barium
The utility reported: 0.124 ppm
Reported range: ND - 0.134
Legal limit (MCL): 1 · Health goal (PHG): 2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits
Inorganic chemicals · report p. 8 · official report
Bromate
The utility reported: Not detected at the report's stated reporting limit ppb
Reported range: ND - 1.6
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
Inorganic chemicals · report p. 8 · official report
Chlorine
The utility reported: 2.5 ppm
Reported range: 1.5 - 3.9
Legal limit (MCL): 4.0 · Health goal (PHG): 4.0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Drinking water disinfectant added for treatment
Inorganic chemicals · report p. 8 · official report
Hexavalent Chromium
The utility reported: 0.1 ppb
Reported range: ND - 0.19
Legal limit (MCL): 10 · Health goal (PHG): 0.02 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits; industrial discharge
Inorganic chemicals · report p. 8 · official report
Fluoride naturally-occurring
The utility reported: 0.35 ppm
Reported range: ND - 0.83
Legal limit (MCL): 2 · Health goal (PHG): 1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits; IRWD does not add Fluoride to its local treated groundwater and surface water
Inorganic chemicals · report p. 8 · official report
Fluoride treatment-related
The utility reported: 0.7 ppm
Reported range: 0.6 - 0.8
Control range: 0.6 - 1.2 · Health goal (Optimal level): 0.7 — not an enforceable limit
Violation per report: No
Typical source, per the report: Water additive for dental health
Inorganic chemicals · report p. 8 · official report
Nitrate
The utility reported: 2.3 ppm as N
Reported range: ND - 4.3
Legal limit (MCL): 10 · Health goal (PHG): 10 — not an enforceable limit
Violation per report: No
Typical source, per the report: Fertilizers, septic tanks
Inorganic chemicals · report p. 8 · official report
Nitrate+Nitrite
The utility reported: 2.3 ppm as N
Reported range: ND - 4.3
Legal limit (MCL): 10 · Health goal (PHG): 10 — not an enforceable limit
Violation per report: No
Typical source, per the report: Fertilizers, septic tanks
Inorganic chemicals · report p. 8 · official report
Irvine Ranch Water District — unregulated monitoring and secondary (aesthetic) records (30)
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.
Germanium, total
The utility reported: 0.82 ppb
Reported range: ND - 1.1
Unregulated chemicals requiring monitoring in the distribution system · report p. 7 · official report
Manganese, total
The utility reported: 1.6 ppb
Reported range: 0.8 - 2.2
Unregulated chemicals requiring monitoring in the distribution system · report p. 7 · official report
Aluminum
The utility reported: 8.4 ppb
Reported range: ND - 110
Typical source, per the report: Treatment process residue, natural deposits
Secondary standards · report p. 8 · official report
Chloride
The utility reported: 112 ppm
Reported range: 17.8 - 124
Typical source, per the report: Leaching from natural deposits; seawater influence
Secondary standards · report p. 8 · official report
Color
The utility reported: <3 color units
Reported range: ND - 8
Typical source, per the report: Naturally-occurring organic substances
Secondary standards · report p. 8 · official report
Odor
The utility reported: 2 TON
Reported range: ND - 6
Typical source, per the report: Naturally-occurring organic materials
Secondary standards · report p. 8 · official report
Specific Conductance
The utility reported: 1065 µmho/cm
Reported range: 358 - 1126
Typical source, per the report: Ions in water; seawater influence
Secondary standards · report p. 8 · official report
Sulfate
The utility reported: 237 ppm
Reported range: 21.5 - 253
Typical source, per the report: Runoff or leaching from natural deposits
Secondary standards · report p. 8 · official report
Total Dissolved Solids
The utility reported: 642 ppm
Reported range: 134 - 738
Typical source, per the report: Runoff or leaching from natural deposits
Secondary standards · report p. 8 · official report
Turbidity
The utility reported: <0.10 NTU
Reported range: ND - 0.4
Typical source, per the report: Erosion of natural deposits
Secondary standards · report p. 8 · official report
Alkalinity, total
The utility reported: 124 ppm as CaCO3
Reported range: 70 - 233
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Bicarbonate
The utility reported: 124 ppm as HCO3
Reported range: 70 - 144
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Boron
The utility reported: 0.16 ppm
Reported range: ND - 0.25
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Bromide
The utility reported: 0.14 ppm
Reported range: 0.02 - 0.29
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Calcium
The utility reported: 72.7 ppm
Reported range: 16.7 - 79.5
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Carbonate
The utility reported: <0.6 ppm
Reported range: <0.6 - 1.1
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Chlorate
The utility reported: 77.0 ppb
Reported range: 77.0
Typical source, per the report: Byproduct of drinking water chlorination
Unregulated contaminants · report p. 8 · official report
Corrosivity (Aggressiveness)
The utility reported: 12.5
Reported range: 11.0 - 12.9
Typical source, per the report: Elemental balance in water
Unregulated contaminants · report p. 8 · official report
Corrosivity (Langlier Index)
The utility reported: 0.62
Reported range: (-)0.72 - 0.81
Typical source, per the report: Elemental balance in water
Unregulated contaminants · report p. 8 · official report
Hardness, total
The utility reported: 295 ppm as CaCO3
Reported range: 53.9 - 321
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Hardness, total
The utility reported: 17.3 grains/gal
Reported range: 7.5 - 17.3
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Magnesium
The utility reported: 27.9 ppm
Reported range: 2.9 - 29.8
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Molybdenum
The utility reported: 7.9 ppb
Reported range: ND - 19.1
Typical source, per the report: Drinking water treatment chemical for aesthetic quality
Unregulated contaminants · report p. 8 · official report
N-Nitrosodi-n-butylamine (NDBA)
The utility reported: 2.5 ppt
Reported range: 2.5
Typical source, per the report: Byproducts of drinking water chloramination; industrial processes
Unregulated contaminants · report p. 8 · official report
Perfluorooctanoic acid (PFOA)
The utility reported: 1.5 ppt
Reported range: ND - 2.4
Typical source, per the report: used in fire-retarding foams and various industrial processes
Unregulated contaminants · report p. 8 · official report
pH
The utility reported: 8.3 pH units
Reported range: 7.1 - 8.6
Typical source, per the report: Acidity, hydrogen ions
Unregulated contaminants · report p. 8 · official report
Potassium
The utility reported: 5.9 ppm
Reported range: 0.65 - 21.2
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Sodium
The utility reported: 105 ppm
Reported range: 25.1 - 116
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
Total Organic Carbon
The utility reported: 1.9 ppm
Reported range: 0.37 - 2.5
Typical source, per the report: Various natural and man-made sources
Unregulated contaminants · report p. 8 · official report
Vanadium
The utility reported: 4.0 ppb
Reported range: ND - 6.3
Typical source, per the report: Runoff or leaching from natural deposits
Unregulated contaminants · report p. 8 · official report
The Three C's — 3 of 3
Corrosion
What conditions could influence pipes, fixtures, and a water heater?
Mesa Water District
Alkalinity, total
The utility reported: 143 ppm as CaCO3
Groundwater · report p. PAGE 6 · official report
Alkalinity, total
The utility reported: 114 ppm as CaCO3
Treated Surface Water · report p. PAGE 7 · official report
Gross Alpha Particle Activity
The utility reported: Not detected at the report's stated reporting limit pCi/L
Reported range: ND - 3.77
Typical source, per the report: Erosion of Natural Deposits
Reported constituent · report p. PAGE 6 · official report
Copper
The utility reported: 0.087 ppm
Typical source, per the report: Corrosion of Household Plumbing
Reported constituent · report p. PAGE 6 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit ppb
Typical source, per the report: Corrosion of Household Plumbing
Reported constituent · report p. PAGE 6 · official report
Irvine Ranch Water District
Alkalinity, total
The utility reported: 124 ppm as CaCO3
Unregulated contaminants · report p. 8 · official report
Lead
The utility reported: <5 ppb
Lead and copper action levels at residential taps · report p. 7 · official report
Copper
The utility reported: 0.1908 ppm
Lead and copper action levels at residential taps · report p. 7 · official report
Alpha Radiation
The utility reported: 1.9 pCi/L
Reported range: ND - 3.8
Typical source, per the report: Erosion of natural deposits
Radiologicals · report p. 8 · official 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 — Mesa Water District
Water Quality 2025 REPORT · data year 2024 · 2024 data retained; monitor for the next official update
View the 2024 Mesa Water District Consumer Confidence ReportSource water, per the report: Mesa Water provides 100% local water that is a blend of local groundwater sources pumped from Orange County’s natural underground reservoir via nine wells. Mesa Water supplements its groundwater with water from the Mesa Water Reliability Facility (MWRF), which pulls source water from deep below ground. If needed as backup supply, Mesa Water can import water from the Municipal Water District of Orange County (MWDOC), which delivers water supplies imported by Metropolitan from the State Water Project and the Colorado River.
Official report — Irvine Ranch Water District
2025 Water Quality Report · data year 2024 · 2024 data retained; monitor for the next official update
View the 2024 Irvine Ranch Water District Consumer Confidence ReportSource water, per the report: IRWD water comes from local groundwater, recycled water, local surface water (rainwater capture), and from imported water from Northern California and the Colorado River. Your drinking water is a blend of local groundwater, groundwater from the Orange County Groundwater Basin managed by the Orange County Water District (OCWD), and to a lesser degree surface water imported by Metropolitan Water District of Southern California (MWD), which comes from the State Water Project and the Colorado River Aqueduct. IRWD also has a local watershed that feeds rainwater to Irvine Lake, which IRWD uses as a surface water source.
Nearby 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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