- EPA's UCMR 5 testing looked for 30 contaminants here and found 6.
- PFOA (a PFAS): found in 1 of 36 samples, average 0.80 ppt, highest 30 ppt (EPA UCMR 5 testing, Feb 2023–Feb 2024)
- PFBA (a PFAS): found in 2 of 36 samples, average 0.30 ppt, highest 6.4 ppt (EPA UCMR 5 testing, Feb 2023–Feb 2024)
- PFPeA (a PFAS): found in 2 of 36 samples, average 0.30 ppt, highest 6.7 ppt (EPA UCMR 5 testing, Feb 2023–Feb 2024)
- PFHxA (a PFAS): found in 1 of 36 samples, average 0.20 ppt, highest 7.1 ppt (EPA UCMR 5 testing, Feb 2023–Feb 2024)
- PFOS (a PFAS): found in 1 of 36 samples, average 0.10 ppt, highest 5.2 ppt (EPA UCMR 5 testing, Feb 2023–Feb 2024)
- PFHxS (a PFAS): found in 1 of 36 samples, average 0.10 ppt, highest 4.2 ppt (EPA UCMR 5 testing, Feb 2023–Feb 2024)
- Lead, 90th percentile: 0.6 ppb at the latest result in EPA records for a monitoring period that ran on or after July 1, 2021, at or below EPA's 15 ppb action level (EPA SDWIS, monitoring period Jan 1, 2022–Dec 31, 2024). The 90th percentile is a system-wide measure from homes sampled under EPA's lead rule; it isn't a result for your home.
Public EPA test results
Can you drink Ontario tap water? What EPA records show
EPA CA3610034 · serves Ontario, CA · about 185,010 people (EPA SDWIS)
This report shows EPA's federal records for this water system: UCMR 5 testing, lead testing and violations. It isn't a test of the water at your tap, and it has no Water Score.
Public EPA test results
Ontario Municipal Utilities Company (EPA CA3610034)
EPA data as of October 14, 2026. For Ontario's main utility, Ontario Municipal Utilities Company: We found no health-based violations in EPA's records for this system (CA3610034) since July 1, 2021, as of October 14, 2026. EPA's UCMR 5 testing looked for 30 contaminants here and found 6. This is public data, not a test of your tap.
What EPA records show for Ontario Municipal Utilities Company, as of October 14, 2026
We found no health-based violations in EPA's records for this system (CA3610034) since July 1, 2021, as of October 14, 2026.
Source: EPA ECHO record for Ontario Municipal Utilities Company (SDWIS). Data as of October 14, 2026.
Lead, 90th percentile: 0.6 ppb at the latest result in EPA records for a monitoring period that ran on or after July 1, 2021, at or below EPA's 15 ppb action level (EPA SDWIS, monitoring period Jan 1, 2022–Dec 31, 2024). The 90th percentile is a system-wide measure from homes sampled under EPA's lead rule; it isn't a result for your home.
EPA's UCMR 5 testing looked for 30 contaminants here and found 6.
Source: EPA records (SDWIS, UCMR 5). SDWIS: data as of Oct 14, 2026. EPA UCMR 5 data, samples through June 2026.
Your water bill names your utility.
Does Ontario Municipal Utilities Company use chloramine?
We didn't find chloramine in Ontario Municipal Utilities Company's EPA treatment records. That's not a complete list; your utility's annual water quality report says which disinfectant it uses.