Serving roughly 114,925 people in Butte County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
🏠Local Expertise
Results for CAL-WATER SERVICE CO.-CHICO
1 water provider directly on file, serving roughly 114,925 people in Butte County, California.
Quick answer: CAL-WATER SERVICE CO.-CHICO has no violations on file. One reading is worth knowing about: Chloride was measured at 9.5MG/L, among the highest of the 160 providers on file in this area. It's the most notable figure in this system's record among its 160 local peers.
Lead Summary
PFOS
PFHXS
Lithium
PFBS
PFOA
PFPEA
PFHXA
Aggressive Index
Langelier Index (pH(s))
Sulfate
Chloride
Orthophosphate
Magnesium
Potassium
Sodium
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
Hardness, Total (ASCACO3)
TDS
Fluoride
Nitrate
Nitrate-Nitrite
Perfluorobutanesulfonicacid (PFBS)
Perfluorohexanesulfonicacid (PFHxS)
Perfluoroctanesulfonicacid (PFOS)
Perfluoroctanoicacid (PFOA)
Perfluoropentanesulfonicacid (PFPES)
Perfluorohexanoicacid (PFHXA)
Perfluoroheptanoicacid (PFHPA)
Perfluoropentanoicacid (PFPEA)
Perfluorobutanoicacid (PFBA)
Utility CAL-WATER SERVICE CO.-CHICOPopulation served 114,925Owner 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)
12/31/2023
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Sulfate
Detected: 6.9 MG/L (ppm)
9/15/2025
Chloride
Detected: 9.5 MG/L (ppm)
9/15/2025
Fluoride
Detected: 0.1 MG/L (ppm)
8/12/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate
Detected: 2.5 MG/L (ppm)
9/15/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Nitrate-Nitrite
Detected: 0.69 MG/L (ppm)
4/23/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 11 MG/L (ppm)
7/9/2025
Potassium
Detected: 1 MG/L (ppm)
7/9/2025
Sodium
Detected: 13 MG/L (ppm)
7/9/2025
Calcium
Detected: 17 MG/L (ppm)
7/9/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Langelier Index (pH(s))
Detected: -0.86 LANG
4/23/2025
Orthophosphate
Detected: 0.3 MG/L (ppm)
6/23/2025
Hardness, Total (ASCACO3)
Detected: 110 MG/L (ppm)
4/23/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
PFOS
Detected: 0.0056 µg/L (ppb)
7/16/2024
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHXS
Detected: 0.0089 µg/L (ppb)
7/16/2024
Lithium
Detected: 11.7 µg/L (ppb)
7/16/2024
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
PFBS
Detected: 0.003 µg/L (ppb)
6/19/2024
PFOA
Detected: 0.0068 µg/L (ppb)
4/9/2024
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFPEA
Detected: 0.0053 µg/L (ppb)
4/9/2024
PFHXA
Detected: 0.006 µg/L (ppb)
4/9/2024
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 120 MG/L (ppm)
4/23/2025
Other
Additional substances tested that don't fit neatly into the categories above
Aggressive Index
Detected: 11.2 AGGR
4/23/2025
Alkalinity, Total
Detected: 120 MG/L (ppm)
4/23/2025
TDS
Detected: 200 MG/L (ppm)
4/23/2025
Perfluorobutanesulfonicacid (PFBS)
Detected: 2.7 NG/L (ppt)
10/21/2025
Perfluorohexanesulfonicacid (PFHxS)
Detected: 7.4 NG/L (ppt)
10/21/2025
Perfluoroctanesulfonicacid (PFOS)
Detected: 6.2 NG/L (ppt)
10/21/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluoroctanoicacid (PFOA)
Detected: 4.8 NG/L (ppt)
10/21/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluoropentanesulfonicacid (PFPES)
Detected: 2.1 NG/L (ppt)
10/8/2025
Perfluorohexanoicacid (PFHXA)
Detected: 3.3 NG/L (ppt)
10/21/2025
Perfluoroheptanoicacid (PFHPA)
Detected: 2 NG/L (ppt)
10/21/2025
Perfluoropentanoicacid (PFPEA)
Detected: 3.9 NG/L (ppt)
10/21/2025
Perfluorobutanoicacid (PFBA)
Detected: 2.3 NG/L (ppt)
1/8/2025
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.