What's in CHINO HILLS, CITY OF's water?
CHINO HILLS, CITY OF has a health-based violation on record, but none in the last five years - an older issue, not necessarily a current one. 76,414 people get their water from it, across 21,799 connections.
How this compares nationally
5 total violations and 2 health-based ones put CHINO HILLS, CITY OF at the 47th percentile nationally for violation burden, rank 6,839 of 12,903.
How CHINO HILLS, CITY OF compares within CA
CHINO HILLS, CITY OF's 2 health-based violations sit within the CA average of 5.8, across 803 systems statewide. See the lead and copper guide for why lead counts differently.
Most recent violation on record
The last violation EPA has on record for CHINO HILLS, CITY OF is from 1994-01-07 (health-based: 1994-01-07). Last reported to EPA: 06/22/2026.
What kind of problem, specifically
CHINO HILLS, 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: Coliform (TCR)
- Nitrate / nitrite - flagged from: Nitrate
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 this data is and is not
This is what CHINO HILLS, 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. Water quality can still change between the meter and the faucet - household plumbing sits outside what a record of 5 logged violations can see. The guide to what this data misses covers that gap.