Serving roughly 39,730 people in Los Angeles County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for GSWC - CLAREMONT
1 water provider directly on file, serving roughly 39,730 people in Los Angeles County, California.
Quick answer: GSWC - CLAREMONT has no violations on file. One reading is worth knowing about: Lead Summary was measured at 0.0056mg/L, among the highest of the 601 providers on file in this area. It's the most notable figure in this system's record among its 601 local peers.
Lead Summary
PFPEA
PFHXA
PFOA
PFHXS
PFHPA
PFBS
PFOS
Lead
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromoform
Bromodichloromethane
Dibromochloromethane
Dichloroaceticacid
Trichloroaceticacid
Dibromoaceticacid
Copper, Free
Nitrate
Perfluorobutanesulfonicacid (PFBS)
Perfluoroheptanoicacid (PFHPA)
Perfluorohexanesulfonicacid (PFHxS)
Perfluoroctanoicacid (PFOA)
Perfluorohexanoicacid (PFHXA)
Perfluoropentanoicacid (PFPEA)
Perfluorobutanoicacid (PFBA)
Utility GSWC - CLAREMONTPopulation served 39,730Owner Private
No violations on file
Contaminants found
Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.0056 mg/L (ppm)
12/31/2026
Lead
Detected: 2.1 UG/L (ppb)
9/22/2025
A metal that can leach from old pipes, solder, and fixtures. Current medical guidance holds there is no truly safe level of lead exposure, especially for children and pregnant women.
Copper, Free
Detected: 31 UG/L (ppb)
9/22/2025
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 9.9 UG/L (ppb)
10/6/2025
TTHM
Detected: 43 UG/L (ppb)
10/6/2025
A group of disinfection byproducts formed when chlorine reacts with organic matter. Long-term exposure above the legal limit has been linked to increased cancer risk in some studies.
Chloroform
Detected: 12 UG/L (ppb)
10/6/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromoform
Detected: 2.7 UG/L (ppb)
10/6/2025
Bromodichloromethane
Detected: 16 UG/L (ppb)
10/6/2025
Dibromochloromethane
Detected: 12 UG/L (ppb)
10/6/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Nitrate
Detected: 0.38 MG/L (ppm)
10/20/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
PFPEA
Detected: 0.0031 µg/L (ppb)
6/4/2024
PFHXA
Detected: 0.004 µg/L (ppb)
6/4/2024
PFOA
Detected: 0.0044 µg/L (ppb)
6/4/2024
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHXS
Detected: 0.0032 µg/L (ppb)
3/19/2024
PFHPA
Detected: 0.003 µg/L (ppb)
3/19/2024
PFBS
Detected: 0.003 µg/L (ppb)
6/4/2024
PFOS
Detected: 0.0104 µg/L (ppb)
9/27/2023
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Other
Additional substances tested that don't fit neatly into the categories above
Dichloroaceticacid
Detected: 4.3 UG/L (ppb)
10/6/2025
Trichloroaceticacid
Detected: 3.6 UG/L (ppb)
10/6/2025
Dibromoaceticacid
Detected: 2 UG/L (ppb)
10/6/2025
Perfluorobutanesulfonicacid (PFBS)
Detected: 2.6 NG/L (ppt)
3/3/2025
Perfluoroheptanoicacid (PFHPA)
Detected: 2.2 NG/L (ppt)
3/3/2025
Perfluorohexanesulfonicacid (PFHxS)
Detected: 2.1 NG/L (ppt)
2/24/2025
Perfluoroctanoicacid (PFOA)
Detected: 4.3 NG/L (ppt)
3/3/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorohexanoicacid (PFHXA)
Detected: 3.9 NG/L (ppt)
3/3/2025
Perfluoropentanoicacid (PFPEA)
Detected: 3.1 NG/L (ppt)
2/24/2025
Perfluorobutanoicacid (PFBA)
Detected: 2 NG/L (ppt)
2/24/2025
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.