CALIFORNIA WATER SERVICE - STOCKTON Water Quality Report
Serving roughly 176,266 people in San Joaquin County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for CALIFORNIA WATER SERVICE - STOCKTON
1 water provider directly on file, serving roughly 176,266 people in San Joaquin County, California.
Quick answer: CALIFORNIA WATER SERVICE - STOCKTON has no violations on file and no single reading stands out against its peers (571 other providers in this area). It serves roughly 176,266 people, and the full breakdown below reflects everything EPA and California have on record for it.
Lead Summary
PFOS
Aggressive Index
Langelier Index (pH(s))
Alkalinity, Total
Alkalinity, Bicarbonate
Magnesium
Calcium
Potassium
Sodium
Hardness, Total (ASCACO3)
Orthophosphate
Foamingagents (SURFACTANTS)
TDS
Chloride
Sulfate
Fluoride
Nitrite
Nitrate
Nitrate-Nitrite
Perfluorohexanesulfonicacid (PFHxS)
Perfluoroctanesulfonicacid (PFOS)
Perfluoroctanoicacid (PFOA)
Utility CALIFORNIA WATER SERVICE - STOCKTONPopulation served 176,266Owner Private
No violations on file
Contaminants found
Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0 mg/L (ppm)
12/31/2024
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 10 MG/L (ppm)
8/13/2025
Sulfate
Detected: 16 MG/L (ppm)
9/9/2025
Fluoride
Detected: 0.1 MG/L (ppm)
9/9/2025
Often added deliberately for dental health; can also occur naturally.
Nitrite
Detected: 0.4 MG/L (ppm)
6/9/2025
Nitrate
Detected: 7.4 MG/L (ppm)
9/9/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Nitrate-Nitrite
Detected: 2.5 MG/L (ppm)
8/13/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 22 MG/L (ppm)
9/9/2025
Calcium
Detected: 44 MG/L (ppm)
9/9/2025
Potassium
Detected: 3.3 MG/L (ppm)
9/9/2025
Sodium
Detected: 37 MG/L (ppm)
9/9/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Langelier Index (pH(s))
Detected: -0.32 LANG
8/13/2025
Hardness, Total (ASCACO3)
Detected: 159 MG/L (ppm)
8/13/2025
Orthophosphate
Detected: 0.3 MG/L (ppm)
8/13/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
PFOS
Detected: 0.0052 µg/L (ppb)
2/5/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 170 MG/L (ppm)
8/13/2025
Other
Additional substances tested that don't fit neatly into the categories above
Aggressive Index
Detected: 11.7 AGGR
8/13/2025
Alkalinity, Total
Detected: 170 MG/L (ppm)
8/13/2025
Foamingagents (SURFACTANTS)
Detected: 0.087 MG/L (ppm)
5/6/2025
TDS
Detected: 270 MG/L (ppm)
8/13/2025
Perfluorohexanesulfonicacid (PFHxS)
Detected: 3.6 NG/L (ppt)
10/14/2025
Perfluoroctanesulfonicacid (PFOS)
Detected: 6.7 NG/L (ppt)
10/14/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluoroctanoicacid (PFOA)
Detected: 2.4 NG/L (ppt)
6/18/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Filtration considerations: See the table below for how whole-house carbon, under-sink reverse osmosis, and under-sink carbon systems compare against what's actually on file here. These are general system types, not a specific product recommendation.