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Water system · PWSID CA3610034

ONTARIO MUNICIPAL UTILITIES COMPANY

ONTARIO, CA · ~185,010 people served

Check your exact address → ONTARIO overview
52
Fair
PurityRadar safety score

PWSID

CA3610034

State

California

City

ONTARIO

Population served

185,010

Primary source

SWP

Score history

▼ 48 points — the score moved from 100 to 52 on Jun 18, 2026, as newly published EPA data was incorporated.

Jun 18, 2026 · score 100 Jun 18, 2026 · score 52

2 score updates logged since tracking began Jun 18, 2026. Each future EPA re-score adds a point.

PFAS & contaminant readings

Latest detections from EPA’s UCMR5 monitoring (through Aug 2023). Levels in parts per trillion (ppt).

PFOA

Perfluorooctanoic acid

30 ppt

limit 4 ppt

Above EPA limit · 7.5×

PFOS

Perfluorooctanesulfonic acid

5.2 ppt

limit 4 ppt

Above EPA limit · 1.3×

PFHxS

Perfluorohexanesulfonic acid

4.2 ppt

limit 10 ppt

Below EPA limit

PFHxA

7.1 ppt

limit —

No federal limit

PFBA

6.4 ppt

limit —

No federal limit

PFPeA

4.8 ppt

limit —

No federal limit

Violations & enforcement

1

Violations on record

0

Unaddressed

1

Health-based

9

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Mar 2000. Official EPA record →

Treatment technique · EPA contaminant 0200 health-based began Jun 1993 Resolved

Recent enforcement actions

  • EPA/federal action · EOX Mar 2000
  • State action · SOX Sep 1994
  • State action · SFK May 1994
  • State action · SOX May 1994
  • EPA/federal action · EOX Dec 1993
  • EPA/federal action · EO+ Nov 1993
  • State action · SFL Jul 1993
  • EPA/federal action · EFL Dec 1992

Area water-quality monitoring

Environmental monitoring (rivers, wells, intakes) recorded in this system’s service area in the EPA/USGS Water Quality Portal since 2018 — source/ambient water, not finished tap water. Context for the watershed, not a reading from your tap.

ContaminantMedian · max · samples

Nitrate

2 stations · latest May 2022

3.27 · max 3.48 mg/l as N · 4

Arsenic

2 stations · latest May 2022

0.515 · max 0.55 ug/l · 2

Fluoride

2 stations · latest May 2022

0.165 · max 0.17 mg/l · 2

Uranium

2 stations · latest May 2022

0.717 · max 0.836 ug/l · 2

Source: Water Quality Portal (EPA/USGS/state agencies). Values are as-reported and aren’t health thresholds.

This profile is built from EPA public records for system CA3610034 — SDWIS violations and UCMR5 PFAS sampling. The score is system-level and can’t account for your home’s plumbing (older pipes can add lead at the tap). For health decisions, check your exact address, read the utility’s Consumer Confidence Report, and confirm with your provider.