Your Local Water Profile: Simi Valley
This profile explains what the applicable water provider reported for Simi Valley, 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
Ventura County Waterworks District No. 8
The report lists hardness as 195 ppm; this is very hard on the USGS scale.
Reported range: 182 - 207 ppm
USGS hardness scale: 0–60 soft; 61–120 moderately hard; 121–180 hard; >180 very hard, in mg/L as CaCO3.
Golden State Water Company
The report lists hardness as 210 mg/L as CaCO3; 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.
Ventura County Waterworks District No. 8 — compliance, as reported
The report states: “The City/District diligently safeguards its water supplies and once again, we are proud to report that your tap water met all U.S. Environmental Protection Agency (U.S. EPA) and State drinking water health standards. [p. 2]”
Simi Valley Water System — compliance, as reported
The report states: “We are proud to report that the water delivered to your tap complies with all applicable regulatory requirements. [p. 2]”
The Three C's — 1 of 3
Chemistry
What does this water tend to do in a home?
Ventura County Waterworks District No. 8
Hardness (Total Hardness)
The utility reported: 195 ppm
Reported range: 182 - 207
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Hardness (Total Hardness)
The utility reported: 148 ppm
Reported range: 143 - 153
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Hardness (Total Hardness)
The utility reported: 163 ppm
Reported range: 160 - 165
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Calcium
The utility reported: 58 ppm
Reported range: 54 - 61
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Calcium
The utility reported: 38 ppm
Reported range: 38 - 39
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Calcium
The utility reported: 37 ppm
Reported range: 36 - 38
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Magnesium
The utility reported: 12.2 ppm
Reported range: 11.4 - 13
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Magnesium
The utility reported: 14 ppm
Reported range: 13 - 14
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Magnesium
The utility reported: 17 ppm
Reported range: 17
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
pH
The utility reported: 7.3 pH Units
Reported range: 6.8 - 7.8
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
pH
The utility reported: 8.3 pH Units
Reported range: 8.2 - 8.3
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
pH
The utility reported: 8.2 pH Units
Reported range: 8.1 - 8.3
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Alkalinity, total as CaCO3
The utility reported: 140 ppm
Reported range: 130 - 160
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Alkalinity, total as CaCO3
The utility reported: 98 ppm
Reported range: 94 - 101
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Alkalinity, total as CaCO3
The utility reported: 125 ppm
Reported range: 120 - 130
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Total Dissolved Solids
The utility reported: 344.4 ppm
Reported range: 320 - 390
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Total Dissolved Solids
The utility reported: 306 ppm
Reported range: 291 - 322
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Total Dissolved Solids
The utility reported: 430 ppm
Reported range: 410 - 450
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Chloride
The utility reported: 19 ppm
Reported range: 19
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Chloride
The utility reported: 40 ppm
Reported range: 39 - 41
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Chloride
The utility reported: 99 ppm
Reported range: 99 - 100
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Sulfate
The utility reported: 125 ppm
Reported range: 120 - 130
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Sulfate
The utility reported: 90 ppm
Reported range: 89 - 92
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Sulfate
The utility reported: 103 ppm
Reported range: 102 - 103
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Sodium
The utility reported: 35 ppm
Reported range: 35
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Sodium
The utility reported: 46 ppm
Reported range: 46
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Sodium
The utility reported: 89 ppm
Reported range: 86 - 91
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Total Chlorine Residual
The utility reported: 2.38 ppm
Reported range: 1.16 - 2.80
DISTRIBUTION WATER QUALITY · report p. 9 · official report
Total Chlorine Residual
The utility reported: 2.11 ppm
Reported range: 0.50 - 3.16
DISTRIBUTION WATER QUALITY · report p. 9 · official report
Total Chlorine Residual
The utility reported: 2.3 ppm
Reported range: 1.7 - 2.8
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Corrosivity (AI)
The utility reported: 11.7 AI
Reported range: 11.4 - 12.1
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Corrosivity (AI)
The utility reported: 12.2 AI
Reported range: 12.2
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Corrosivity (AI)
The utility reported: 12.3 AI
Reported range: 12.1 - 12.4
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Simi Valley Water System
Hardness
The utility reported: 210 mg/L as CaCO3
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Hardness
The utility reported: 12 grains/gal
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Calcium
The utility reported: 54 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Magnesium
The utility reported: 20 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
pH
The utility reported: 8.1 pH units
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Alkalinity
The utility reported: 120 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Total Dissolved Solids
The utility reported: 500 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Chloride
The utility reported: 79 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Sulfate
The utility reported: 150 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Sodium
The utility reported: 78 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Lead 90th percentile
The utility reported: Not detected at the report's stated reporting limit µg/L
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
Copper 90th percentile
The utility reported: 0.48 mg/L
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
Chloramines
The utility reported: 1.8 mg/L
Simi Valley Water System – Distribution Water Quality · report p. 9 · 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.
Ventura County Waterworks District No. 8 — regulated contaminants reported as detected (30)
Lead
The utility reported: 0.001 ppm
AL: 15 · Health goal (PHG): 0.2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits; internal corrosion of house pipes
DISTRIBUTION WATER QUALITY · report p. 9 · official report
Copper
The utility reported: 0.11 ppm
AL: 1.3 · Health goal (PHG): 0.3 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits; internal corrosion of house pipes
DISTRIBUTION WATER QUALITY · report p. 9 · official report
Total Chlorine Residual
The utility reported: 2.38 ppm
Reported range: 1.16 - 2.80
MRDL: 4 · Health goal (MRDLG): 4 — not an enforceable limit
Violation per report: No
Typical source, per the report: Drinking water disinfectant added for treatment
DISTRIBUTION WATER QUALITY · report p. 9 · official report
Total Chlorine Residual
The utility reported: 2.11 ppm
Reported range: 0.50 - 3.16
MRDL: 4 · Health goal (MRDLG): 4 — not an enforceable limit
Violation per report: No
Typical source, per the report: Drinking water disinfectant added for treatment
DISTRIBUTION WATER QUALITY · report p. 9 · official report
Haloacetic Acids
The utility reported: 6.2 ppb
Reported range: 0.0 - 14.0
Legal limit (MCL): 60
Violation per report: No
Typical source, per the report: By-product of drinking water disinfection
DISTRIBUTION WATER QUALITY · report p. 9 · official report
Total Trihalomethane
The utility reported: 5.3 ppb
Legal limit (MCL): 80
Violation per report: No
Typical source, per the report: By-product of drinking water disinfection
DISTRIBUTION WATER QUALITY · report p. 9 · official report
Total Trihalomethane
The utility reported: 17.7 ppb
Reported range: 8.6 - 35
Legal limit (MCL): 80
Violation per report: No
Typical source, per the report: By-product of drinking water disinfection
DISTRIBUTION WATER QUALITY · report p. 9 · official report
Turbidity
The utility reported: <0.1 NTU
TT: Highest Single Value
Violation per report: No
Typical source, per the report: Soil runoff
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Turbidity
The utility reported: 0.04 NTU
TT: Highest Single Value
Violation per report: No
Typical source, per the report: Soil runoff
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Turbidity
The utility reported: 0.14 NTU
TT: Highest Single Value
Violation per report: No
Typical source, per the report: Soil runoff
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Aluminum
The utility reported: 62 ppb
Reported range: 52 - 91
Legal limit (MCL): 1000 · Health goal (PHG): 600 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits; residual from water treatment processes
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Arsenic
The utility reported: 0.96 ppb
Reported range: 0.96
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; runoff from orchards
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Arsenic
The utility reported: 3 ppb
Reported range: 2.0 - 4.0
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; runoff from orchards
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Chromium (hexavalent)
The utility reported: 0.09 ppb
Reported range: 0.044 - 0.18
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; natural transformation from trivalent chromium
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Fluoride
The utility reported: 0.7 ppm
Reported range: 0.6 - 1.0
Legal limit (MCL): 2.0 · Health goal (PHG): 1.0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Water additive that promotes strong teeth
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Nitrate (as N)
The utility reported: 0.69 ppm
Reported range: 0.69
Legal limit (MCL): 10 · Health goal (PHG): 10.0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Runoff & leaching from fertilizer use; erosion of natural deposits
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Nitrate (as N)
The utility reported: 0.5 ppm
Reported range: 0.5
Legal limit (MCL): 10 · Health goal (PHG): 10.0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Runoff & leaching from fertilizer use; erosion of natural deposits
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Selenium
The utility reported: 11 ppb
Reported range: 11
Legal limit (MCL): 50 · Health goal (PHG): 30 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits; discharge from refineries
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Gross Alpha Particle Activity
The utility reported: 5.62 pCi/L
Reported range: 5.62
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
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Gross Beta Particle Activity
The utility reported: 2.49 pCi/L
Reported range: 2.49
Legal limit (MCL): 50 · Health goal (PHG): (0) — not an enforceable limit
Violation per report: No
Typical source, per the report: Decay of natural & man-made deposits
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Gross Beta Particle Activity
The utility reported: 5.5 pCi/L
Reported range: 5.4 - 5.6
Legal limit (MCL): 50 · Health goal (PHG): (0) — not an enforceable limit
Violation per report: No
Typical source, per the report: Decay of natural & man-made deposits
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Uranium
The utility reported: 4.2 pCi/L
Reported range: 4.2
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
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Uranium
The utility reported: 2 pCi/L
Reported range: 2.0 - 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
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Uranium
The utility reported: 1.5 pCi/L
Reported range: 1.4 - 1.5
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
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Bromate
The utility reported: 3.1 ppb
Reported range: ND - 5.4
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
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Haloacetic Acids
The utility reported: 12.0 ppb
Reported range: 6.0 - 22.0
Legal limit (MCL): 60
Violation per report: No
Typical source, per the report: By-product of drinking water disinfection
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Total Chlorine Residual
The utility reported: 2.38 ppm
Reported range: 1.16 - 2.80
MRDL: 4.0 · Health goal (MRDLG): 4.0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Drinking water disinfectant added for treatment
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Total Chlorine Residual
The utility reported: 2.3 ppm
Reported range: 1.7 - 2.8
MRDL: 4.0 · Health goal (MRDLG): 4.0 — not an enforceable limit
Violation per report: No
Typical source, per the report: Drinking water disinfectant added for treatment
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Total Trihalomethane
The utility reported: 5.3 ppb
Legal limit (MCL): 80
Violation per report: No
Typical source, per the report: By-product of drinking water disinfection
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Total Trihalomethane
The utility reported: 21.8 ppb
Reported range: 13.0 - 36.0
Legal limit (MCL): 80
Violation per report: No
Typical source, per the report: By-product of drinking water disinfection
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Ventura County Waterworks District No. 8 — unregulated monitoring and secondary (aesthetic) records (21)
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: 62 ppb
Reported range: 52 - 91
Typical source, per the report: Erosion of natural deposits; residual from some water treatment process
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Color
The utility reported: 1 Units
Reported range: 1
Typical source, per the report: Naturally occurring organic materials
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Odor
The utility reported: 1 TON Units
Reported range: 1
Typical source, per the report: Naturally occurring organic materials
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Specific Conductance
The utility reported: 543 µS/cm
Reported range: 510 - 1100
Typical source, per the report: Substances that form ions when in water; seawater influence
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Specific Conductance
The utility reported: 510 µS/cm
Reported range: 498 - 522
Typical source, per the report: Substances that form ions when in water; seawater influence
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Specific Conductance
The utility reported: 782 µS/cm
Reported range: 773 - 790
Typical source, per the report: Substances that form ions when in water; seawater influence
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Zinc
The utility reported: 0.011 ppm
Reported range: 0.011
Typical source, per the report: Runoff/leaching from natural deposits
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Zinc
The utility reported: 0.06 ppm
Reported range: 0.06
Typical source, per the report: Runoff/leaching from natural deposits
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Boron
The utility reported: 0.17 ppm
Reported range: 0.17
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Boron
The utility reported: 0.17 ppm
Reported range: 0.17
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Boron
The utility reported: 0.28 ppm
Reported range: 0.27 - 0.28
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Chlorate
The utility reported: 57 ppb
Reported range: 57
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Chlorate
The utility reported: 71 ppb
Reported range: 71
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Potassium
The utility reported: 1.4 ppm
Reported range: 1.4
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Potassium
The utility reported: 2.6 ppm
Reported range: 2.6
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Potassium
The utility reported: 4.0 ppm
Reported range: 4.0
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Total Organic Carbon
The utility reported: 0.57 ppm
Reported range: 0.57
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Total Organic Carbon
The utility reported: 2.4 ppm
Reported range: 2.0 - 2.5
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Total Organic Carbon
The utility reported: 2.7 ppm
Reported range: 2.6 - 2.8
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Vanadium
The utility reported: 4.3 ppb
Reported range: 4.3
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Radon
The utility reported: 390.5 pCi/L
Reported range: 390.5
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Simi Valley Water System — regulated contaminants reported as detected (17)
Turbidity (Highest single measurement)
The utility reported: 0.16 NTU
TT: 1.0
Violation per report: No
Typical source, per the report: Soil runoff
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Turbidity (Lowest percent of all monthly readings less than 0.3 NTU)
The utility reported: 100% %
TT: 95
Violation per report: No
Typical source, per the report: Soil runoff
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Aluminum
The utility reported: Not detected at the report's stated reporting limit mg/L
Reported range: ND - 0.079
Legal limit (MCL): 1 · Health goal (PHG): 0.6 — not an enforceable limit
Violation per report: No
Typical source, per the report: Erosion of natural deposits; residue from some surface water treatment processes
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Arsenic
The utility reported: Not detected at the report's stated reporting limit µg/L
Reported range: ND - 2
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; runoff from orchards; glass and electronics production wastes
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Fluoride
The utility reported: 0.7 mg/L
Reported range: 0.2 - 1.1
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 that promotes strong teeth; discharge from fertilizer and aluminum factories
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Nitrate [as N]
The utility reported: 1.2 mg/L
Reported range: ND - 4.8
Legal limit (MCL): 10 · Health goal (PHG): 10 — not an enforceable limit
Violation per report: No
Typical source, per the report: Runoff and leaching from fertilizer use; leaching from septic tanks and sewage; erosion of natural deposits
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Perchlorate
The utility reported: Not detected at the report's stated reporting limit µg/L
Reported range: ND - 1.2
Legal limit (MCL): 6 · Health goal (PHG): 1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Perchlorate is an inorganic chemical used in solid rocket propellant, fireworks, explosives, flares, matches, and a variety of industries. It usually gets into drinking water as a result of environmental contamination from historic aerospace or other industrial operations that used or use, store, or dispose of perchlorate and its salts.
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Selenium
The utility reported: 7.7 µg/L
Reported range: ND - 19
Legal limit (MCL): 50 · Health goal (PHG): 30 — not an enforceable limit
Violation per report: No
Typical source, per the report: Discharge from petroleum, glass, and metal refineries; erosion of natural deposits; discharge from mines and chemical manufacturers; runoff from livestock lots (feed additive)
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Gross Alpha Activity
The utility reported: 1.4 pCi/L
Reported range: ND - 4.2
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
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Gross Beta Activity
The utility reported: 5.4 pCi/L
Reported range: ND - 9.1
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 manmade deposits
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Uranium
The utility reported: 3.8 pCi/L
Reported range: 1.2 - 8.0
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
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Bromate
The utility reported: 4.1 µg/L
Reported range: ND - 6.7
Legal limit (MCL): 10 · Health goal (MRDLG): 0.1 — not an enforceable limit
Violation per report: No
Typical source, per the report: Byproduct of drinking water disinfection
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
Chloramines [as Cl2]
The utility reported: 1.8 mg/L
Reported range: 0.4 - 3.4
MRDL: 4.0 · Health goal (MRDLG): 4 — not an enforceable limit
Violation per report: No
Typical source, per the report: Drinking water disinfectant added for treatment
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
HAA5 [Sum of 5 Haloacetic Acids]
The utility reported: 4.7 µg/L
Reported range: ND - 5.5
Legal limit (MCL): 60
Violation per report: No
Typical source, per the report: Byproduct of drinking water disinfection
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
TTHMs [Total Trihalomethanes]
The utility reported: 16 µg/L
Reported range: 6.5 - 25
Legal limit (MCL): 80
Violation per report: No
Typical source, per the report: Byproduct of drinking water disinfection
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
Copper
The utility reported: 0.48 mg/L
Reported range: None of the 35 samples collected exceeded the action level.
AL: 1.3 · Health goal (PHG): 0.3 — not an enforceable limit
Violation per report: No
Typical source, per the report: Internal corrosion of household plumbing systems; erosion of natural deposits; leaching from wood preservatives
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit µg/L
Reported range: None of the 35 samples collected exceeded the action level.
AL: 15 · Health goal (PHG): 0.2 — not an enforceable limit
Violation per report: No
Typical source, per the report: Internal corrosion of household water plumbing systems; discharges from industrial manufacturers; erosion of natural deposits.
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
Simi Valley Water System — unregulated monitoring and secondary (aesthetic) records (15)
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 µg/L
Reported range: ND - 79
Typical source, per the report: Erosion of natural deposits; residue from some surface water treatment processes
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Color
The utility reported: Not detected at the report's stated reporting limit units
Reported range: ND - 1
Typical source, per the report: Naturally-occurring organic materials
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Chloride
The utility reported: 79 mg/L
Reported range: 46 - 100
Typical source, per the report: Runoff/leaching from natural deposits; seawater influence
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Specific Conductance
The utility reported: 700 µS/cm
Reported range: 503 - 1,000
Typical source, per the report: Substances that form ions when in water; seawater influence
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Sulfate
The utility reported: 150 mg/L
Reported range: 64 - 330
Typical source, per the report: Runoff/leaching from natural deposits; industrial wastes
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Total Dissolved Solids
The utility reported: 500 mg/L
Reported range: 293 - 800
Typical source, per the report: Runoff/leaching from natural deposits
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Alkalinity
The utility reported: 120 mg/L
Reported range: 96 - 150
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Calcium
The utility reported: 54 mg/L
Reported range: 31 - 92
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Hardness [as CaCO3]
The utility reported: 210 mg/L
Reported range: 137 - 330
Typical source, per the report: The sum of polyvalent cations present in the water, generally magnesium and calcium; the cations are usually naturally occurring
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Hardness [as CaCO3]
The utility reported: 12 grains/gal
Reported range: 8.0 - 19
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Magnesium
The utility reported: 20 mg/L
Reported range: 13 - 29
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
pH
The utility reported: 8.1 pH units
Reported range: 7.9 - 8.4
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Potassium
The utility reported: 3.4 mg/L
Reported range: 2.8 - 4.0
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Sodium
The utility reported: 78 mg/L
Reported range: 46 - 100
Typical source, per the report: Refers to the salt present in the water and is generally naturally occurring
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Lithium
The utility reported: 17 ug/L
Reported range: ND - 36
Typical source, per the report: Naturally-occurring; used in electrochemical cells, batteries, and organic syntheses and pharmaceuticals
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
The Three C's — 3 of 3
Corrosion
What conditions could influence pipes, fixtures, and a water heater?
Ventura County Waterworks District No. 8
pH
The utility reported: 7.3 pH Units
Reported range: 6.8 - 7.8
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
pH
The utility reported: 8.3 pH Units
Reported range: 8.2 - 8.3
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
pH
The utility reported: 8.2 pH Units
Reported range: 8.1 - 8.3
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Alkalinity, total as CaCO3
The utility reported: 140 ppm
Reported range: 130 - 160
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Alkalinity, total as CaCO3
The utility reported: 98 ppm
Reported range: 94 - 101
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Alkalinity, total as CaCO3
The utility reported: 125 ppm
Reported range: 120 - 130
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Chloride
The utility reported: 19 ppm
Reported range: 19
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Chloride
The utility reported: 40 ppm
Reported range: 39 - 41
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Chloride
The utility reported: 99 ppm
Reported range: 99 - 100
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Sulfate
The utility reported: 125 ppm
Reported range: 120 - 130
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Sulfate
The utility reported: 90 ppm
Reported range: 89 - 92
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Sulfate
The utility reported: 103 ppm
Reported range: 102 - 103
SECONDARY DRINKING WATER STANDARDS · report p. 10 · official report
Gross Alpha Particle Activity
The utility reported: 5.62 pCi/L
Reported range: 5.62
Typical source, per the report: Erosion of natural deposits
PRIMARY DRINKING WATER STANDARDS · report p. 9 · official report
Simi Valley Water System
pH
The utility reported: 8.1 pH units
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Alkalinity
The utility reported: 120 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Chloride
The utility reported: 79 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Sulfate
The utility reported: 150 mg/L
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Lead 90th percentile
The utility reported: Not detected at the report's stated reporting limit µg/L
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
Copper 90th percentile
The utility reported: 0.48 mg/L
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
Gross Alpha Activity
The utility reported: 1.4 pCi/L
Reported range: ND - 4.2
Typical source, per the report: Erosion of natural deposits
Simi Valley Water System – Treated Source Water Quality · report p. 8 · official report
Copper
The utility reported: 0.48 mg/L
Reported range: None of the 35 samples collected exceeded the action level.
Typical source, per the report: Internal corrosion of household plumbing systems; erosion of natural deposits; leaching from wood preservatives
Simi Valley Water System – Distribution Water Quality · report p. 9 · official report
Lead
The utility reported: Not detected at the report's stated reporting limit µg/L
Reported range: None of the 35 samples collected exceeded the action level.
Typical source, per the report: Internal corrosion of household water plumbing systems; discharges from industrial manufacturers; erosion of natural deposits.
Simi Valley Water System – Distribution Water Quality · report p. 9 · 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 — Ventura County Waterworks District No. 8
2024 ANNUAL WATER QUALITY REPORT · data year 2024 · 2024 data retained; monitor for the next official update
View the 2024 Ventura County Waterworks District No. 8 Consumer Confidence ReportSource water, per the report: The primary supply is surface water from the State Water Project imported from Northern California, treated at Metropolitan Water District's Joseph Jensen Filtration Plant, and conveyed to Calleguas Municipal Water District. Colorado River water serves as a secondary supply source for Calleguas. Calleguas also uses Lake Bard Reservoir and Water Filtration Facility to store imported water. Calleguas supplies approximately 99% of the drinking water. The other 1% is groundwater from the Gillibrand Groundwater Basin, treated at the Tapo Canyon Water Treatment Plant.
Official report — Simi Valley Water System
2026 Annual Water Quality Report · data year 2025 · Current 2025 monitoring cycle
View the 2025 Simi Valley Water System Consumer Confidence ReportSource water, per the report: The primary source of water delivered to customers in the Simi Valley System is treated surface water purchased from the Calleguas Municipal Water District, which obtains its supply from the Metropolitan Water District of Southern California. This primary source of water is blended with groundwater from the Simi Valley Groundwater Basin. The State Water Board approved blending plan consists of tested groundwater (18%), blended with treated Calleguas MWD water (82%), and tested again before being distributed to customers.
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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