GOLDEN STATE WATER COMPANY - LOS OSOS Water Quality Report
Serving roughly 5,924 people in San Luis Obispo County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for GOLDEN STATE WATER COMPANY - LOS OSOS
1 water provider directly on file, serving roughly 5,924 people in San Luis Obispo County, California.
Quick answer: GOLDEN STATE WATER COMPANY - LOS OSOS has no violations on file. One reading is worth knowing about: Chloride was measured at 240MG/L, among the highest of the 252 providers on file in this area. It's the most notable figure in this system's record among its 252 local peers.
Lead Summary
Lithium
PFHXA
PFBS
PFHXS
PFPEA
TTHM
Chloroform
Bromoform
Bromodichloromethane
Dibromochloromethane
Nitrate
Perfluorobutanesulfonicacid (PFBS)
Perfluorohexanesulfonicacid (PFHxS)
Perfluoroctanoicacid (PFOA)
Perfluorohexanoicacid (PFHXA)
Perfluoropentanoicacid (PFPEA)
Perfluoropentanesulfonicacid (PFPES)
Chromium, Hex
TDS
Chloride
Utility GOLDEN STATE WATER COMPANY - LOS OSOSPopulation served 5,924Owner 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
Chromium, Hex
Detected: 6.9 UG/L (ppb)
7/1/2025
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
TTHM
Detected: 5 UG/L (ppb)
7/1/2025
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: 0.54 UG/L (ppb)
7/1/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromoform
Detected: 1.7 UG/L (ppb)
7/1/2025
Bromodichloromethane
Detected: 1.1 UG/L (ppb)
7/1/2025
Dibromochloromethane
Detected: 1.7 UG/L (ppb)
7/1/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Nitrate
Detected: 4.5 MG/L (ppm)
10/28/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Chloride
Detected: 240 MG/L (ppm)
10/28/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 9.6 µg/L (ppb)
8/9/2023
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
PFHXA
Detected: 0.004 µg/L (ppb)
12/20/2023
PFBS
Detected: 0.0032 µg/L (ppb)
2/6/2023
PFHXS
Detected: 0.0081 µg/L (ppb)
12/20/2023
PFPEA
Detected: 0.0033 µg/L (ppb)
12/20/2023
Other
Additional substances tested that don't fit neatly into the categories above
Perfluorobutanesulfonicacid (PFBS)
Detected: 2.6 NG/L (ppt)
10/7/2025
Perfluorohexanesulfonicacid (PFHxS)
Detected: 8.8 NG/L (ppt)
10/7/2025
Perfluoroctanoicacid (PFOA)
Detected: 4 NG/L (ppt)
10/7/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorohexanoicacid (PFHXA)
Detected: 4.3 NG/L (ppt)
10/7/2025
Perfluoropentanoicacid (PFPEA)
Detected: 2.5 NG/L (ppt)
10/7/2025
Perfluoropentanesulfonicacid (PFPES)
Detected: 2 NG/L (ppt)
10/7/2025
TDS
Detected: 490 MG/L (ppm)
10/28/2025
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.