Mason City Water Department

Water Quality Snapshot: Mason City Water Department

Mason City Water Department is a local-owned community water system that delivers drinking water to 27,338 residents in Mason City, Iowa (Cerro Gordo County) through 19,000 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 647 total violations for this system , of which 68 (11%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 429 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.

The most frequently cited contaminant at this system is Combined Radium (-226 and -228), recorded in 123 violations (Other). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

Across Iowa, EPA tracks 1,795 public water systems serving 3,114,444 people, with 138,271 cumulative violations and 27,946 health-based violations on record. About 95% of systems in the state carry at least one violation, and state-wide the average per system is 77 violations. Statewide, 127 of 152 UCMR5-tested systems have reported PFAS detections (83.6%).

Mason City Water Department's 647 violations sit above the Iowa average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.