No health-based violations on EPA record since 2016.
Serves about 7,086 people (2,776 connections) with groundwater from its own wells, and buys water from Golden State Water Company.
From EPA's record for CA4010016. PurityMap is independent of Los Osos Community Services District.
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No health-based violations in the last 10 years, from EPA's SDWIS compliance database.
EPA required this system to test for 30 unregulated and emerging contaminants, from January 2024 to July 2024.
| Contaminant | Result | Limit | Status | Sampled | Source |
|---|---|---|---|---|---|
| Perfluorooctanoic acid (PFOA) | 14.7 ng/L | 4.0 ng/L federal MCL (2024) | Above a historical reference; current applicability unverified | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorooctanesulfonic acid (PFOS) | 11.7 ng/L | 4.0 ng/L federal MCL (2024) | Above a historical reference; current applicability unverified | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Lithium | 16.1 µg/L | 10 µg/L EPA health reference level (screening, not a legal limit)Screening level, not a legal limit | Above the referenced health-based guidance value | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorohexanesulfonic acid (PFHxS) | 8.4 ng/L | 10 ng/L federal MCL (2024) | Within a historical reference; current applicability unverified | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorobutanesulfonic acid (PFBS) | 18 ng/L | 2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limit | Within the referenced health-based guidance value | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorohexanoic acid (PFHxA) | 16.6 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Within a historical reference; current applicability unverified | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorobutanoic acid (PFBA) | 6 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluoroheptanoic acid (PFHpA) | 5.4 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluoropentanoic acid (PFPeA) | 16.8 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-07-08 | UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016) |
Screening tells you if something is worth a closer look; a lab result is the number you can act on.
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Screening: quick check, not lab-grade
Safe Home (EnviroTestKits)
Lead, read as one of three ranges: 0–4, 5–15 or 15+ ppb
Turnaround: 5 minutes
What it can't tell you: It shows a lead range, not an exact level, and tests nothing else unless you pay extra for the optional lab test.
Lab-certified results
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
Environmental Testing and Research Laboratories (ETR Labs), Leominster, MA · ISO/IEC 17025:2017, ANAB certificate AT-2638 · 2–4 business days after the lab receives it
What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.
Get PurityMap updates about this water system.
Follow this water →Los Osos Community Services District's phone number on EPA record is 805-528-9379. Its mailing address is 2122 9th Street Suite 110, LOS OSOS, CA 93402.
According to EPA's record, Los Osos Community Services District uses groundwater from its own wells, and buys water from Golden State Water Company.
No health-based violations on EPA record since 2016. EPA also lists 1 missed or late test or report in 10 years. The record comes from EPA's SDWIS compliance database.
The 90th-percentile lead result in Los Osos Community Services District's latest lead and copper round, which ended in December 2026, was 1.1 µg/L, below the federal action level of 15 µg/L.
PurityMap has no verified website for Los Osos Community Services District. Its phone number on EPA record is 805-528-9379. Its mailing address on EPA record is 2122 9th Street Suite 110, LOS OSOS, CA 93402. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.