Oconomowoc Waterworks, WI Water Quality
Oconomowoc Waterworks: EPA violation history, explained
Oconomowoc Waterworks has a health-based violation on record, but none in the last five years - an older issue, not necessarily a current one. 15,805 people get their water from it, across 1 connections.
Ranked against every other system in this dataset
Out of 12,903 systems in this dataset, Oconomowoc Waterworks ranks 5,318th by violation burden (59th percentile) - 9 violations total, 3 health-based.
Against the WI average
Oconomowoc Waterworks's 3 health-based violations sit within the WI average of 5.4, across 259 systems statewide. See the lead and copper guide for why lead counts differently.
Most recent violation on record
Oconomowoc Waterworks's most recent violation on record is dated 2014-01-01, with the most recent health-based one dated 2001-01-11. Last reported to EPA: 05/29/2026.
The concern categories on record
Oconomowoc Waterworks'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)
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 Oconomowoc Waterworks's record does not cover
Oconomowoc Waterworks's numbers here come from its own required reporting to EPA under the Safe Drinking Water Act, not from an independent test of your glass of water. This record - 3 health-based violations on file for Oconomowoc Waterworks - stops at the meter and cannot see household plumbing on the other side of it. The guide to what this data misses covers that gap.