Drinking water quality · 2026
· Verified
· PWSID CA3610038
What's in Rialto, City of, CA tap water
Only 1 of 27 core regulated contaminants were reported for Rialto, City of, CA. What was measured is not clean — but most of the picture is missing.
- !1 contaminant at or above a federal limit — worst is PFOA (Perfluorooctanoic acid) at 1.8x
- !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.
- −22 contaminants at or above a federal limit
- −0 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
- PFOA (Perfluorooctanoic acid)1.8× the federal limit7.3 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 75% of CA systems that report it · higher than 80% of U.S. systems
+6 contaminants were measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| PFHxS (Perfluorohexane sulfonic acid) | 3.5 ng/L | 10 ng/L |
| PFHpA | 3.5 ng/L | — |
| PFBS | 4.6 ng/L | — |
| PFPeA | 18 ng/L | — |
| PFBA | 5.7 ng/L | — |
| PFHxA | 17 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 Rialto, City of, 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)
1 PFAS compound above EPA limits in Rialto, City of, 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.
PFOA (Perfluorooctanoic acid)
● Over EPA limit (1.8×)PFHxS (Perfluorohexane sulfonic acid)
● Below limitPFHpA
● Detected (no federal limit)PFBS
● Detected (no federal limit)PFPeA
● Detected (no federal limit)PFBA
● Detected (no federal limit)PFHxA
● Detected (no federal limit)Where your water comes from · EPA SDWIS
Rialto, City of, CA's drinking water comes from ground water, drawn from 9 sources.
Source
- CITY · 2
- AIRPORT WELL
- CHINO
- MIRO
- + 4 more
Treatment
- RIALTO WELL 05 - TREATED
- CEDAR WELL (RIALTO 01) - TREATED (CL2)
- CITY WELL 01 - TREATED (CL2)
- + 5 more
Distribution
Also buys water from SAN BERNARDINO VALLEY WD, SAN BERNARDINO CITY, and 3 more.
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.
- Maximum contaminant level exceededHealth-based2 violations on record · most recent Aug 1993resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗