Tap water in Ontario, CA — ZIP 91761
2 public water systems serving about 272,965 people. PFAS "forever chemicals" have been detected here.
C
Fair
PFAS detected: at least one system serving this ZIP reported PFAS in EPA UCMR 5
testing. Levels and the 2024 federal limits are shown per system below.
Water systems serving 91761
Ontario Municipal Utilities Company
PWSID CA3610034 · serves 185,010 ·
surface water
0 health-based / 0 total violations (5 yrs)
· PFAS up to 30 ppt — above federal limit
Western Mwd
PWSID CA3310049 · serves 87,955 ·
surface water
0 health-based / 0 total violations (5 yrs)
· PFAS up to 4.7 ppt
Grades summarize EPA SDWIS violation records (last 5 years) and UCMR 5 PFAS results. They are informational, not a health determination. Methodology