US Cities With the Most Water Violations: 2026 Rankings

Each year, thousands of US water utilities report health-based violations to the EPA. By aggregating this data, we can identify which cities and states are struggling most with drinking water compliance.

Methodology

We analyzed all 51 US states and territories using the EPA Safe Drinking Water Information System (SDWIS) for violations occurring between 2021-2026. We counted only health-based MCL exceedances and Treatment Technique violations affecting active Community Water Systems.

The Findings

This ranking changes regularly as new violations are reported and resolved. Visit our Violations Dashboard for the latest numbers.

Common Patterns

States with the most violations tend to share certain characteristics:

1. Many small, rural systems: Small utilities (serving <500 people) account for the majority of violations nationally
2. Aging infrastructure: Cities with pre-1960s plumbing infrastructure see more lead, copper, and disinfection byproduct issues
3. Limited staffing: Rural utilities often lack certified operators
4. Source water challenges: Surface water from rivers and lakes is harder to treat than deep groundwater

Top Contaminant Categories

The most common health-based violations involve:

1. Disinfection Byproducts (TTHMs, HAA5): Form when chlorine reacts with organic matter — affects most surface water systems
2. Coliform Bacteria: Indicator of potential pathogen contamination
3. Lead and Copper: Action level exceedances from corroded plumbing
4. Nitrates: Common in agricultural regions
5. Arsenic: Naturally occurring in certain geological regions (Southwest)

How to Use This Information

A city appearing on a "worst" list doesn't necessarily mean the water is dangerous today. It means historic violations have been recorded — most have since been resolved. The most important thing you can do is:

1. Check current water quality reports for your specific utility
2. Sign up for utility alerts about new violations
3. Use appropriate filtration for any persistent issues
4. Engage with local utility board meetings to push for infrastructure investment

Use TapSafeWater to look up your city's current grade and violation count.