States With the Most Drinking Water Violations (EPA SDWIS Totals)
Which U.S. states record the most Safe Drinking Water Act violations in EPA SDWIS? Ranked by total violation counts across public water systems, not a consumer safety score.
Research period:
Pennsylvania leads this EPA SDWIS ranking with 1,159,868 total drinking-water violations recorded across 7,701 public water systems. Totals aggregate system citations, not a safety or taste score.
Research question
Across US states in the EPA SDWIS dataset, which carry the highest total drinking-water-act violation counts, and how do health-based violations compare to the overall total?
How to read this list
The board orders the 10 highest state totals in EPA SDWIS. Total violations include several compliance categories; the health-based column is shown separately because raw totals alone do not establish current household risk or water quality. Each state link opens its full profile, and the source links below identify the federal records used.
Values reflect the current PlainWater extract of EPA SDWIS records. EPA may revise coverage and state reporting practices, so compare this ranking as a starting point for investigation rather than a safety or taste verdict. See the methodology page for source scope, update history, and corrections.
States with the most SDWIS drinking-water violations
Updated automatically as new data is published
The ranked top 10
Every row below reflects the current dataset. Refresh the page after new data is published to see the latest values.
| # | State | Total violations | Health-based | Water systems | Population served |
|---|---|---|---|---|---|
| 1 | Pennsylvania | 1,159,868 | 68,517 | 7,701 | 12,630,061 |
| 2 | Texas | 746,210 | 162,945 | 7,351 | 33,253,313 |
| 3 | New York | 552,003 | 26,817 | 8,098 | 19,294,951 |
| 4 | North Carolina | 524,053 | 38,492 | 5,020 | 9,877,724 |
| 5 | Mississippi | 499,292 | 10,292 | 1,185 | 3,286,781 |
| 6 | Illinois | 355,322 | 52,932 | 5,117 | 12,576,876 |
| 7 | Indiana | 352,710 | 35,932 | 3,967 | 5,774,616 |
| 8 | Oklahoma | 336,706 | 113,804 | 1,262 | 3,699,452 |
| 9 | Washington | 314,648 | 20,590 | 4,557 | 9,736,844 |
| 10 | Montana | 297,270 | 25,922 | 2,263 | 1,112,267 |
Source: U.S. Environmental Protection Agency, EPA SDWIS Federal Reporting Data. Values are refreshed automatically whenever the source publishes updated data.
Findings
Top entity in the ranking
The top-ranked record in this dataset is Pennsylvania, with a value of 1,159,868 on the Total violations column. The full top-10 set is rendered in the table above. Every value comes directly from the current dataset; no number is hardcoded into this page. When the source agency publishes a revision, the ranking and the prose around it update automatically.
Distribution shape
The gap between the top-ranked record (1,159,868) and the 10th-ranked record (297,270) characterizes how concentrated the top of the distribution is. Where the top value is many multiples of the median value of the visible set, the population is highly concentrated, a small number of entities accumulate the bulk of the measured quantity. Where the top and bottom of the visible set are close together, the distribution is relatively flat across the top end. The full distribution beyond this top-10 cut is summarized in the aggregate context section below and explored in the linked entity profiles.
Aggregate context
Across the full population behind this ranking, here are the summary statistics: how many records exist in total, the sum of the ranking metric across all qualifying records, and the mean per-record value. The methodology page documents the exact filter applied (records with null or zero values on the ranking metric are excluded). This aggregate row is computed from the same dataset that powers the ranking above.
Source provenance
The records in this ranking originate from U.S. Environmental Protection Agency, specifically the EPA SDWIS Federal Reporting Data. PlainWater ingests the source vintage published by the agency and keeps this page in sync with it, there is no static export carrying stale numbers, and an updated dataset is reflected here within hours of publication. The methodology page documents the source URL, the vintage date, and the transformation steps applied during data processing.
Why this ranking matters
Rankings like this one let a reader scan a population quickly and identify outliers, concentrations, and patterns that warrant deeper investigation. The detail pages linked from each entity in the table above give the full per-entity context: time-series history where available, related metrics from adjacent tables, and links onward to the underlying source records. The methodology page explains how an entity earns inclusion in the dataset and how the ranking column is computed at the source.
What this analysis cannot tell us
Violation counts aggregate every recorded SDWIS violation regardless of severity, duration, or whether the violation has since been resolved. A single water-system error or reporting lapse can generate many separate violations under different rule categories, inflating raw counts relative to population health risk. States with larger populations of community water systems and more aggressive enforcement reporting may appear to have higher violation totals not because their water is less safe but because their reporting is more thorough. Monitoring and reporting violations are mixed into the total alongside genuine maximum-contaminant-level exceedances, only the health_violations column attempts to isolate the public-health-significant subset. Federal SDWIS data lags real-time water-system performance by months to years depending on each primacy agency's reporting cadence. Some primacy agencies (state environment departments) report differently than others, introducing comparability friction across state lines.
Secondary cut from the same source
Top 10 states by health-based SDWIS violations, a subset of total violations classified by EPA as health-significant
Sources
- EPA Safe Drinking Water Information System (SDWIS) - https://www.epa.gov/enviro/sdwis-search
- EPA Drinking Water Compliance Reports - https://www.epa.gov/dwreginfo
- EPA National Public Water Systems Compliance Report - https://www.epa.gov/dwreginfo/national-public-water-systems-compliance-report
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.