Drinking Water Systems in ONTARIO, Oregon
1 water system are reported for this city, with a combined service population of 14,465. The systems have 7 EPA violation records in the five-year period ending June 30, 2026.
Water Systems Serving ONTARIO
EPA Contaminant Categories in Historical Violation Records
Coliform (TCR)11 records
Surface Water Treatment Rule11 records
Interim Enhanced Surface Water Treatment Rule6 records
Haloacetic Acids (HAA5)4 records
Total Trihalomethanes (TTHMs)4 records
Arsenic2 records
Beryllium1 record
Cyanide1 record
Thallium, Total1 record
1,2,4-Trichlorobenzene1 record
Category counts aggregate historical compliance records across listed systems. They do not show current concentrations or household test results.