Golden State Water Company - Los Osos
Published drinking-water records and contacts for Golden State Water Company - Los Osos. System CA4010017. Review sources and dates; not a real-time water assessment.
- System ID
- CA4010017
- State or territory
- CA
- Published population served
- 5924
- System type (source code)
- CWS
Published records and dates
- PFAS / lithium (EPA UCMR 5): 240 — 2023-02-06 – 2024-04-30
- Lead and copper monitoring summaries: 47 — 1992-01-01 – 2026-12-31
- California DDW laboratory results: 735 — 2026-01-06 – 2026-07-14
Missing records here do not mean the provider did not test. Published records are not a real-time assessment of your tap water.
Published testing results
Selected recent records are shown below. Different sampling locations and dates are not interchangeable. These excerpts are not a complete testing history.
“<” means below the stated reporting limit, not zero. A reported measurement alone is not a safety verdict. Read an example
| Substance | Published result | Reporting limit | Sample date | Sampling location |
|---|---|---|---|---|
| 11Cl-PF3OUdS | < 0.005 µg/L | 0.005 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| 4:2 FTS | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| 6:2 FTS | < 0.005 µg/L | 0.005 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| 8:2 FTS | < 0.005 µg/L | 0.005 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| 9Cl-PF3ONS | < 0.002 µg/L | 0.002 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| ADONA | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| HFPO-DA | < 0.005 µg/L | 0.005 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| NEtFOSAA | < 0.005 µg/L | 0.005 µg/L | 2023-10-04 | Los Olivos Resv Nitrate Blend Effluent / 4010017020 |
| NFDHA | < 0.02 µg/L | 0.02 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| NMeFOSAA | < 0.006 µg/L | 0.006 µg/L | 2023-10-04 | Los Olivos Resv Nitrate Blend Effluent / 4010017020 |
| PFBA | < 0.005 µg/L | 0.005 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFBS | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFDA | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFDoA | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFEESA | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFHpA | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFHpS | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFHxA | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFHxS | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFMBA | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFMPA | < 0.004 µg/L | 0.004 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFNA | < 0.004 µg/L | 0.004 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFOA | < 0.004 µg/L | 0.004 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFOS | < 0.004 µg/L | 0.004 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFPeA | < 0.003 µg/L | 0.003 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFPeS | < 0.004 µg/L | 0.004 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| PFTA | < 0.008 µg/L | 0.008 µg/L | 2023-10-04 | Los Olivos Resv Nitrate Blend Effluent / 4010017020 |
| PFTrDA | < 0.007 µg/L | 0.007 µg/L | 2023-10-04 | Los Olivos Resv Nitrate Blend Effluent / 4010017020 |
| PFUnA | < 0.002 µg/L | 0.002 µg/L | 2024-04-30 | Cabrillo Well - Fe/Mn Treated / 4010017015 |
| lithium | < 9 µg/L | 9 µg/L | 2023-08-09 | Rosina IX TP Effluent - Nitrate Treated / 4010017022 |
Download all EPA UCMR 5 records (CSV)
Lead and copper: 90th-percentile summaries
These describe a monitoring period across sampled locations, not the result at your home. How to read the 90th percentile
| Substance | Published 90th percentile | Monitoring period | Source quarter |
|---|---|---|---|
| Lead (PB90) | 0.0028 mg/L | 2024-01-01 – 2026-12-31 | 2026Q3 |
| Lead (PB90) | 0 mg/L | 2021-01-01 – 2023-12-31 | 2026Q3 |
| Lead (PB90) | 0.0046 mg/L | 2018-01-01 – 2020-12-31 | 2026Q3 |
| Lead (PB90) | 0 mg/L | 2015-01-01 – 2017-12-31 | 2026Q3 |
| Lead (PB90) | 0.0031 mg/L | 2012-01-01 – 2014-12-31 | 2026Q3 |
| Lead (PB90) | 0.0031 mg/L | 2009-01-01 – 2011-12-31 | 2026Q3 |
| Lead (PB90) | 0.0079 mg/L | 2006-01-01 – 2008-12-31 | 2026Q3 |
| Lead (PB90) | 0.0088 mg/L | 2003-01-01 – 2005-12-31 | 2026Q3 |
| Substance | Published result | Sample date | Location / source |
|---|---|---|---|
| NITRATE | 6.8 MG/L | 2026-07-14 | CABRILLO WELL / California DDW laboratory results |
| MANGANESE | < 10.000000000 UG/L | 2026-07-14 | SOUTH BAY WELL 01 - FE/MN TREATED / California DDW laboratory results |
| CHROMIUM, HEX | 9.5 UG/L | 2026-07-14 | LOS OLIVOS WELL 05 / California DDW laboratory results |
| TDS | 310 MG/L | 2026-07-14 | ROSINA WELL / California DDW laboratory results |
| NITRATE | 4.5 MG/L | 2026-07-14 | ROSINA IX TP EFFLUENT - NITRATE TREATED / California DDW laboratory results |
| NITRATE | 4.4 MG/L | 2026-07-14 | LOS OLIVOS RESV NITRATE BLEND INFLUENT / California DDW laboratory results |
| IRON | < 50.000000000 UG/L | 2026-07-14 | SOUTH BAY WELL 01 / California DDW laboratory results |
| NITRATE | 4.3 MG/L | 2026-07-14 | LOS OLIVOS RESV NITRATE BLEND EFFLUENT / California DDW laboratory results |
| CHLORIDE | 100 MG/L | 2026-07-14 | ROSINA WELL / California DDW laboratory results |
| MANGANESE | < 10.000000000 UG/L | 2026-07-14 | SOUTH BAY WELL 01 / California DDW laboratory results |
| CHROMIUM, HEX | 6.8 UG/L | 2026-07-14 | LOS OLIVOS RESV NITRATE BLEND EFFLUENT / California DDW laboratory results |
| CHROMIUM, HEX | 5.1 UG/L | 2026-07-14 | LOS OLIVOS WELL 03 / California DDW laboratory results |
State sampling points can include untreated water. Publisher qualifiers and units are retained; consult the full source notes before interpreting a record.
Download state records with source notes (CSV)
Published compliance history
0 imported records. Status is as recorded in the source; historical records are not current advisories. Missing records do not establish that no violations occurred.
Source dates and refresh checks
A refresh check is not a sample date. Publication periods, sample dates and checks are shown separately.
- EPA SDWIS lead/copper summaries and service areas — source period: — – —; last checked: 2026-10-17
- EPA SDWIS contacts and compliance records — source period: — – —; last checked: 2026-10-17
- EPA UCMR 5 sample results — source period: 2023-01-03 – 2026-06-17; last checked: 2026-10-17
- California DDW laboratory results — last successful check: 2026-10-18
Administrative contact (EPA filing)
Kraycik, Enoch: 909-730-1161
An administrative filing contact may not be a customer-service line. Confirm current contact details with the provider.