Short answer: No measured result is above a legal limit; lithium sits above a screening level. Vallecitos Water District serves 114,700 residents.
Your water bill or annual water quality report names your actual supplier.
VALLECITOS WD (EPA PWSID CA3710002) delivers surface water to 114,700 residents. This report reflects 29 individual PFAS result(s) from the source UCMR5 observations and the latest Lead & Copper Rule 90th-percentile result. Water hardness and disinfectant type are pending the utility's own annual report.
0health-based violations in the last 10 years
From EPA SDWIS. A clean violation history means no enforcement action was recorded; it does not cover contaminants without a limit.
No result is not a pass. Your utility's annual water quality report may list them, and a certified lab test covers your own tap.
The records describe the system. A certified lab test shows what reaches your glass.
Lithium 52 µg/L, above the 10.0 µg/L EPA health reference level
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
Silver Lake Research
Lead, bacteria, nitrate, copper, iron, chlorine, hardness and pH
What it can't tell you: Each test gives a yes/no or a rough range, not a lab number, and it cannot detect PFAS or arsenic.
Lab-certified results
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
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.
When your results arrive, read them here →
Each card names which San Marcos findings its current certification covers, and which it doesn't.
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No product in our catalogue has verified certification for these concerns yet.
PurityMap does not give a safe/unsafe verdict; it shows what the public records measured. For San Marcos, no regulated PFAS were detected in EPA's 2024 testing. VALLECITOS WD (PWSID CA3710002) has a Purity Score of 100/100 (confidence: moderate), assessed at the water-system level and computed only from contaminants that were measured. Water can change in your own pipes, so a certified test is the only way to know what comes out of your tap.
VALLECITOS WD (PWS ID CA3710002) is the public water system on record for San Marcos, California, serving about 114,700 people. Confirm the utility on your water bill before acting on a specific finding.
Surface water (primary source of record in EPA SDWIS).
None of the 29 PFAS in EPA's UCMR 5 testing (2023-02-07 to 2024-06-04) was detected. "Not detected" means below the lab's reporting limit, not proven zero.
Lead is not in San Marcos's current published record. Lead usually enters from a building's own pipes and fixtures, so a certified home test is the way to know yours.
PurityMap's current record for San Marcos holds 31 findings: 1 above a reference and 30 not detected. Each finding links to its dated public record; a parameter that was never monitored is shown as pending, not as a pass.
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| Contaminant | Result | Benchmark | Status | Sampled | Source |
|---|---|---|---|---|---|
| Lithium | 52 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 | 2023-02-07 to 2023-11-20 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Contaminant | Result | Benchmark | Status | Sampled | Source |
|---|---|---|---|---|---|
| 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 | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| 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 | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| 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 | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| 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 | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| 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 | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Lead (90th percentile) | Non-Detect (ND) | 15 µg/L federal action level | Not detected above the reporting limit | 2024–2026 monitoring period (still open) | Lead & Copper Rule 90th-percentile: VALLECITOS WD (CA3710002) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2023-11-20 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2023-11-20 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorobutanesulfonic acid (PFBS) | < 3 ng/L | 2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limit | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorobutanoic acid (PFBA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorohexanesulfonic acid (PFHxS) | < 3 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorohexanoic acid (PFHxA) | < 3 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluoropentanoic acid (PFPeA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2023-11-20 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2023-11-20 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-02-07 to 2024-06-04 | UCMR5 Analytical Results: VALLECITOS WD (CA3710002) |
11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
Perfluoro-3-methoxypropanoic acid (PFMPA)
Perfluoro-4-methoxybutanoic acid (PFMBA)
Perfluorobutanesulfonic acid (PFBS)
Perfluorododecanoic acid (PFDoA)
Perfluoroheptanesulfonic acid (PFHpS)
Perfluoroheptanoic acid (PFHpA)
Perfluorohexanesulfonic acid (PFHxS)
Perfluorohexanoic acid (PFHxA)
Perfluorooctanesulfonic acid (PFOS)
Perfluoropentanesulfonic acid (PFPeS)
Perfluoropentanoic acid (PFPeA)
Perfluorotetradecanoic acid (PFTA)
Perfluorotridecanoic acid (PFTrDA)
Perfluoroundecanoic acid (PFUnA)
Every value is the published result from the cited public record. A reporting limit is the lowest level the method could reliably quantify; a non-detect is not a guarantee of zero.
UCMR5 Analytical Results
UCMR5 Analytical Results: VALLECITOS WD (CA3710002)
US EPA
State SDWIS Compliance Record
Lead & Copper Rule 90th-percentile: VALLECITOS WD (CA3710002)
US EPA SDWIS
Methodology: how we analyze water. Prepared with AI assistance and reviewed by the PurityMap Editorial Team before publication.
Start with the hot-or-cold tap check. Where Vallecitos Water District reported something related, it's shown below.
Lead at Vallecitos Water District: not detected (90th percentile, 2024–2026 monitoring period (still open)). Lead has no taste, so a taste neither shows nor rules it out.
A ZIP code is a postal area, not a water service area. Your water bill names your supplier.