What's in ONTARIO, CITY OF's water?
ONTARIO, CITY OF has a health-based violation on record, but none in the last five years - an older issue, not necessarily a current one. It serves 14,465 people through 4,082 service connections.
How this compares nationally
102 total violations and 1 health-based ones put ONTARIO, CITY OF at the 44th percentile nationally for violation burden, rank 7,242 of 12,903.
Against the OR average
OR's 160 covered systems average 6.0 health-based violations each; ONTARIO, CITY OF carries 1, not more than typical for the state. The filter guide explains what a violation like this actually calls for.
Most recent violation on record
ONTARIO, CITY OF's most recent violation on record is dated 2023-01-03, with the most recent health-based one dated 2002-01-03. Last reported to EPA: 06/26/2026.
The concern categories on record
ONTARIO, CITY OF's flagged contaminants and rule violations, grouped by what they actually mean for a filter choice rather than left as EPA's raw code list:
- Microbial contamination / treatment technique - flagged from: Surface Water Treatment Rule
The most severe category on record is microbial contamination / treatment technique, which points toward a microbial-class filter if you want to address it directly.
What ONTARIO, CITY OF's record does not cover
This is what ONTARIO, CITY OF reported to its state primacy agency and EPA under the Safe Drinking Water Act - real regulatory record, not a lab test of your specific tap. Between the utility's meter and ONTARIO, CITY OF's customers' taps is household plumbing, invisible to a system-level record ranked 7,242th of 12,903 by violation count. The guide to what this data misses covers that gap.