Drinking water quality · 2023
· Verified
What's in Golden State Water Company - Los Osos, CA tap water
70 contaminants were measured in the Golden State Water Company - Los Osos, CA water system's 2023 annual report. Each is shown below against its federal limit.
- Reporting year
- 2023
- Contaminants measured
- 70
- Over federal limit
- 0
- Approaching the limit
- 1
- Service area
- CA
PFAS — EPA UCMR5 (2023–2025)
1 PFAS compound approaching EPA limits in Golden State Water Company - Los Osos, CA
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFHxS (Perfluorohexane sulfonic acid)
● Approaching limit (88%)near national p90 (12.049999999999997 ng/L across detecting U.S. systems)
PFPeA
● Detected (no federal limit)below national p90 (15.95999999999999 ng/L across detecting U.S. systems)
PFHxA
● Detected (no federal limit)below national p90 (12.190000000000003 ng/L across detecting U.S. systems)
Lithium
● Detected (no federal limit)below national p90 (76.59999999999991 mg/L across detecting U.S. systems)
PFBS
● Detected (no federal limit)below national p90 (13.909999999999979 ng/L across detecting U.S. systems)
Where your water comes from · EPA SDWIS
Golden State Water Company - Los Osos, CA's drinking water comes from ground water, drawn from 6 sources.
Source
- LOS OLIVOS · 2
- CABRILLO WELL
- SOUTH BAY
- ROSINA WELL
- + 1 more
Treatment
- LOS OLIVOS RESV NITRATE BLEND INFLUENT
- SOUTH BAY WELL 01 - TRT CL
- ROSINA WELL - TRT CL
- + 6 more
Distribution
Historical readings · EPA Six-Year Review (2012–2019)
2 contaminants historically over EPA limits in Golden State Water Company - Los Osos, CA
Every U.S. public water system reports compliance-monitoring data to EPA. The Six-Year Review releases the 2012–2019 window as a single dataset — here's what your system reported, year by year. Values shown are the highest detection per analyte per year, compared to the federal MCL.
| Contaminant | Worst detection | EPA limit | Years (2012–2019) |
|---|---|---|---|
NITRATE worst: 2017 | 24 mg/L 2.4× | 10 mg/L | '12'13'14'15'16'17'18'19 |
NITRATE NITRITE worst: 2017 | 21 mg/L 2.1× | 10 mg/L | '17'18 |
CHROMIUM worst: 2015 | 0.015 mg/L within above national p90 | 0.1 mg/L | '15 |
RADIUM 226 228 worst: 2018 | 0.62 pCi/L within below national p90 | 5 pCi/L | '18 |
DICHLOROMETHANE worst: 2017 | 0.0005 mg/L within | 0.005 mg/L | '17 |
HAA5 worst: 2014 | 0.0046 mg/L within | 0.06 mg/L | '14 |
BARIUM worst: 2016 | 0.14 mg/L within near national p90 | 2 mg/L | '12'15'16'19 |
FLUORIDE worst: 2012 | 0.25 mg/L within | 4 mg/L | '12'15'16'18'19 |
TTHM worst: 2016 | 0.0028 mg/L within | 0.08 mg/L | '16'19 |
MCAA worst: 2014 | 0.0046 mg/L | — | '14 |
BROMOFORM worst: 2016 | 0.0013 mg/L | — | '16 |
DIBROMOCHLOROMETHANE worst: 2016 | 0.0015 mg/L | — | '16'19 |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| CopperA metal that enters water from corroding household plumbing. | 836.0000000000001 UG/L90th percentileDistribution | 1300 UG/LAl | Within the limit |
| IronA naturally occurring metal common in groundwater. | 9 UG/LAverageSource water | 300 UG/LMCL | Within the limit |
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| ManganeseA naturally occurring metal from soil and rock. | Not detected UG/LHighest single sampleEntry point | 50 UG/LMCL | None detected |
| Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium. | 8.3 UG/LAverageSource water | None set | Detected — no federal limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Total Dissolved SolidsTotal dissolved solids — the combined content of all dissolved minerals and salts. | 425 MG/LAverageSource water | 1000 MG/LMCL | Within the limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorideA naturally occurring salt compound. | 173.98387096774192 MG/LAverageSource water | 500 MG/LMCL | Within the limit |
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChloroformA trihalomethane formed when chlorine reacts with organic matter in water. | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| BromodichloromethaneA trihalomethane disinfection byproduct. | 1 UG/LAverageDistribution | None set | Detected — no federal limit |
Other
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Carbon Tetrachloride | Not detected UG/LHighest single sampleSource water | 0.5 UG/LMCL | None detected |
| Chlorobenzene | Not detected UG/LHighest single sampleSource water | 70 UG/LMCL | None detected |
| Cis Dichloroethylene 12 | Not detected UG/LHighest single sampleSource water | 6 UG/LMCL | None detected |
| Dbaa | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| Dcaa | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| Dichloroethane 12 | Not detected UG/LHighest single sampleSource water | 0.5 UG/LMCL | None detected |
| Dichloroethylene 11 | Not detected UG/LHighest single sampleSource water | 6 UG/LMCL | None detected |
| Dichloropropane 12 | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Mbaa | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| O Dichlorobenzene | Not detected UG/LHighest single sampleSource water | 600 UG/LMCL | None detected |
| P Dichlorobenzene | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Pce | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Styrene | Not detected UG/LHighest single sampleSource water | 100 UG/LMCL | None detected |
| Tcaa | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| Tce | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Trans Dichloroethylene 12 | Not detected UG/LHighest single sampleSource water | 10 UG/LMCL | None detected |
| Trichlorobenzene 124 | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Trichloroethane 111 | Not detected UG/LHighest single sampleSource water | 200 UG/LMCL | None detected |
| Trichloroethane 112 | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Vinyl Chloride | Not detected UG/LHighest single sampleSource water | 0.5 UG/LMCL | None detected |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid, a chlorinated PFAS compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)ADONA, a newer-generation PFAS replacement compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 4:2 Fluorotelomer sulfonic acid (4:2 FTS)4:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 6:2 Fluorotelomer sulfonic acid (6:2 FTS)6:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 8:2 Fluorotelomer sulfonic acid (8:2 FTS)8:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS)9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid, a chlorinated PFAS compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Hexafluoropropylene oxide dimer acidHFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)N-ethyl perfluorooctanesulfonamidoacetic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)N-methyl perfluorooctanesulfonamidoacetic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro-3-methoxypropanoic acid (PFMPA)Perfluoro-3-methoxypropanoic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro-4-methoxybutanoic acid (PFMBA)Perfluoro-4-methoxybutanoic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA)Perfluoro(2-ethoxyethane)sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorodecanoic acid (PFDA)Perfluorodecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorododecanoic acid (PFDoA)Perfluorododecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroheptanesulfonic acid (PFHpS)Perfluoroheptanesulfonic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorononanoic acidPerfluorononanoic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorotetradecanoic acid (PFTeDA)Perfluorotetradecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorotridecanoic acid (PFTrDA)Perfluorotridecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroundecanoic acid (PFUnA)Perfluoroundecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| PFBAPerfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroheptanoic acidPerfluoroheptanoic acid, a PFAS 'forever chemical.' | 2.1666666666666665 NG/LAverageSource water | None set | Detected — no federal limit |
| Perfluoropentanesulfonic acid (PFPeS)Perfluoropentanesulfonic acid, a PFAS 'forever chemical.' | 1.46 NG/LAverageSource water | None set | Detected — no federal limit |
VOCs & pesticides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| AtrazineA widely used agricultural herbicide that reaches water through runoff. | Not detected UG/LHighest single sampleSource water | 1 UG/LMCL | None detected |
| Benzene | Not detected UG/LHighest single sampleSource water | 1 UG/LMCL | None detected |
| Ethylbenzene | Not detected UG/LHighest single sampleSource water | 300 UG/LMCL | None detected |
| Simazine | Not detected UG/LHighest single sampleSource water | 4 UG/LMCL | None detected |
| Toluene | Not detected UG/LHighest single sampleSource water | 150 UG/LMCL | None detected |
| XylenesA group of industrial solvents found in gasoline and paint. | Not detected UG/LHighest single sampleSource water | 1750 UG/LMCL | None detected |
People also ask about Golden State Water Company - Los Osos, CA's water
+Is Golden State Water Company - Los Osos, CA tap water safe to drink in 2023?
Every one of the 70 contaminants measured in Golden State Water Company - Los Osos, CA's 2023 Consumer Confidence Report is below its federal limit. "Safe" under the EPA's drinking-water standards is health-based, not aesthetic — but by those standards, no measured contaminant in this report exceeds its enforceable threshold. Individual health concerns (e.g. immunocompromised, infant, pregnancy) may warrant additional filtering regardless of compliance.
+What contaminants are in Golden State Water Company - Los Osos, CA tap water?
70 contaminants were measured in Golden State Water Company - Los Osos, CA's 2023 Consumer Confidence Report, spanning pfas ("forever chemicals"), other, and vocs & pesticides. 33 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Are any contaminants in Golden State Water Company - Los Osos, CA tap water approaching the federal limit?
One contaminant is between 80% and 100% of the federal limit in this report: Perfluorohexanesulfonic acid. Approaching means measured but not in violation — a margin that can close quickly if conditions change.
+Where does the data on this page come from?
Every value is transcribed from Golden State Water Company - Los Osos, CA's 2023 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Golden State Water Company - Los Osos, CA's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2023 report; a new report will replace it once the utility publishes its next annual update.