250 active public water systems serve 92,356 people in Ozaukee County. 188 are compliant, 62 had at least one EPA violation in the past three years, 1 is a designated serious violator, and 2 carry a health flag.
Active systems25048 community systems
People served92Kby public water systems
Systems with violations6225% of active systems, past 3 years
Serious violators12 systems carry a health flag
Needs attention
Williamsburg 207 209 and 214WI2460147 · Thiensville · Community water system · Serves 704 rules violated in the past three years. Unresolved: Lead and Copper Rule, Lead and Copper Rule Revisions, and Public Notice Rule and Revised PN Rule.
River Garden AptsWI2460139 · Thiensville · Community water system · Serves 254 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions and Public Notice Rule and Revised PN Rule.
Totals cover active systems. Systems serving more than one county are counted in each county. EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Wisconsin records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.
Compliant
Compliant
No violations reported to EPA in the past three years.
At least one violation on record with EPA in the past three years. Many are monitoring or reporting lapses rather than contamination; the system page lists which rules were involved and whether each is still open.
EPA's designation, also called an enforcement priority, for a system with unresolved serious, multiple, or continuing violations. EPA expects the system and its state to act quickly to resolve them.
At least one open health-based violation: an exceedance of a maximum contaminant level or residual disinfectant level, or a treatment technique violation. Monitoring and reporting lapses do not raise this flag.