Drinking water quality · 2026
· Verified
· PWSID CA4810008
What's in City of Vacaville, CA tap water
Only 1 of 27 core regulated contaminants were reported for City of Vacaville, CA. What was measured is not clean — but most of the picture is missing.
- !2 contaminants at or above a federal limit — worst is PFOS (Perfluorooctane sulfonic acid) at 2.5x
- !1 contaminant within 20% of a limit
- !1 of 27 core regulated contaminants reported — 26 never appear in this report
- ✓No open federal violations
+How this score is calculated
Every system starts at 100. Points come off for measured levels, for the federal violation record, and for how much of the core regulated set the utility actually reported. All three inputs are the utility's own published numbers and EPA's own records.
- −44 contaminants at or above a federal limit
- −4 contaminants within 20% of a limit
- −0 open health-based violations
- −0 open monitoring / reporting violations
- −0 health-based violations resolved in the last 5 years
- −28 core regulated contaminants never reported (1/27)
A 90–100 · B 80–89 · C 70–79 · D 60–69 · F below 60. A system reporting under a third of the core set is capped at C however clean its numbers look — a short report is not a clean bill of health.
Full grading methodology, constant for constant →What to worry about
- PFOS (Perfluorooctane sulfonic acid)2.5× the federal limit10 ng/L · limit 4 ng/L
Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
Higher than 75% of CA systems that report it · higher than 80% of U.S. systems
- PFOA (Perfluorooctanoic acid)1.3× the federal limit5.1000000000000005 ng/L · limit 4 ng/L
Linked to cancer, liver damage, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
Higher than 65% of CA systems that report it · higher than 70% of U.S. systems
- PFHxS (Perfluorohexane sulfonic acid)92% of the federal limit9.2 ng/L · limit 10 ng/L
Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
Higher than 80% of CA systems that report it · higher than 80% of U.S. systems
+1 contaminant was measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| PFBS | 3.7 ng/L | — |
What this report doesn't tell you
26 of the 27 contaminants a community water system normally reports do not appear anywhere in City of Vacaville, CA's data. Absent is not the same as absent-from-the-water — it means nobody published a number.
+Full detail: PFAS testing, water source, historical monitoring, and the federal violation record
PFAS — EPA UCMR5 (2023–2025)
2 PFAS compounds above EPA limits in City of Vacaville, 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.
PFOS (Perfluorooctane sulfonic acid)
● Over EPA limit (2.5×)PFOA (Perfluorooctanoic acid)
● Over EPA limit (1.3×)PFHxS (Perfluorohexane sulfonic acid)
● Approaching limit (92%)PFBS
● Detected (no federal limit)Where your water comes from · EPA SDWIS
City of Vacaville, CA's drinking water comes from ground water, drawn from 15 sources.
Source
- WELL · 11
- DE MELLO WELL - STANDBY
- NBR WTP - NORTH BAY AQUEDUCT - RAW
- NBR WTP - PUTAH SOUTH CANAL - RAW
- + 1 more
Treatment
- WELL 16 - TREATED
- WELL 03 - TREATED
- WELL 05 - TREATED
- + 10 more
Distribution
Also buys water from CITY OF FAIRFIELD.
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.