Perfluorooctanesulfonic acid
4.4ng/L
Each block = 4.0 ng/L federal MCL (2024)
El Monte-City, Water Dept. serves 22,968 people from groundwater. 31 results are on record. PFOS is above its federal limit (a 2024 limit that water systems have until at least 2029 to meet); everything else measured is within its reference or not detected.
The bar is drawn in blocks of the 4.0 ng/L federal MCL (2024), so the length shows how far above it the result sits.
4.4ng/L
Each block = 4.0 ng/L federal MCL (2024)
4,010service lines inventoried
From the utility's inventory reported to EPA (2026Q2). Look up your address with the utility.
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.
A federal limit (an MCL or action level) is an enforceable legal cap; a health goal is often stricter. Meeting the limit is a compliance fact, not a health clearance, and PurityMap publishes no overall compliance verdict.
A tap test can confirm levels at your home before you choose treatment.
PFOS 4.4 ng/L, above the 4 ng/L limit (+1 more PFAS detected)
Understand water treatment technologies →
Understand:PFAS in El Monte
Each card names which of this system’s findings its current certification covers, and which it doesn’t.
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EL MONTE-CITY, WATER DEPT. (PWS ID CA1910038) is a public water system serving 22,968 people in El Monte, California.
EL MONTE-CITY, WATER DEPT. is on record as drawing from groundwater. The source shapes which contaminants matter most for this system.
PurityMap's record for EL MONTE-CITY, WATER DEPT. holds 31 findings: 1 above a reference, 1 detected within the reference and 29 not detected, from 31 evidence records. Every finding links to its source; a substance that was never monitored is shown as pending, not as a pass.
PurityMap does not issue a safety verdict. It publishes EL MONTE-CITY, WATER DEPT.'s measured results against each contaminant's benchmark so you can read them in context. Safety depends on the specific finding, your plumbing, and how the water reaches your tap.
The latest published record for EL MONTE-CITY, WATER DEPT. is dated 2026-09-16. Utilities report on regulatory cycles, so results reflect the monitoring period rather than a live reading.
No. It is assessed at the water-system level from EL MONTE-CITY, WATER DEPT.'s own monitoring. It does not cover the service line to your building or the plumbing inside it, which can add lead and other metals after the water leaves the system. A tap test is the way to know what reaches your glass.
Perfluorooctanesulfonic acid (PFOS) and Perfluorohexanesulfonic acid (PFHxS) were detected in this record. Each finding shows its measured value, its reference and its source on this page.
Start with what the record shows: the PFAS findings above list each measured value against its reference. This record cannot show your home's plumbing, so a tap test tells you what reaches your glass. If you decide to treat your water, look for a filter whose certification covers the specific PFAS compounds in your record; the section "Certified for a concern found here" lists only products with a current certification record for these concerns.
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As listed for this system in EPA's records. Your water bill names your supplier.
| Substance | Result | Reference | Sampled | Status | Evidence |
|---|---|---|---|---|---|
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | < 5 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS) | < 3 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) | < 2 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | 2023-09-21 to 2024-08-05 | Not detected | — |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-03-28 | Not detected | — |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-03-28 | Not detected | — |
| Perfluorobutanoic acid (PFBA) | < 5 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluorobutanesulfonic acid (PFBS) | < 3 ng/L | 2,000 ng/L EPA health advisory (screening, not a legal limit) | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluorohexanoic acid (PFHxA) | < 3 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluorohexanesulfonic acid (PFHxS) | 3.2 ng/L | 10 ng/L federal MCL (2024) | 2023-09-21 to 2024-08-05 | Below limit | View evidence |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | 2023-09-21 to 2024-08-05 | Not detected | View evidence |
| Perfluorooctanesulfonic acid (PFOS) | 4.4 ng/L | 4.0 ng/L federal MCL (2024) | 2023-09-21 to 2024-08-05 | Above guideline | View evidence |
| Perfluoropentanoic acid (PFPeA) | < 3 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-03-28 | Not detected | — |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-03-28 | Not detected | — |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | 2023-09-21 to 2024-08-05 | Not detected | — |
| Lithium | < 9 µg/L | 10 µg/L EPA health reference level (screening, not a legal limit) | 2023-09-21 to 2024-03-28 | Not detected | — |
| Lead (90th percentile) | Non-Detect (ND) | 15 µg/L federal action level | 2024–2026 monitoring period (still open) | Not detected | View evidence |
UCMR5 Analytical Results
UCMR5 Analytical Results: EL MONTE-CITY, WATER DEPT. (CA1910038)
US EPA
State SDWIS Compliance Record
Lead & Copper Rule 90th-percentile: EL MONTE-CITY, WATER DEPT. (CA1910038)
US EPA SDWIS