Drinking-Water Violations by Contaminant
Data current as of March 2026 — recomputed by ZipCheckup from federal data each build.
EPA logs 6,897 drinking-water violations across 7 regulated contaminants, as of March 2026.
EPA records 6,897 drinking-water violations across 7 regulated contaminants, as of March 2026.
By state
| contaminant | violations | violation zips | affected zips |
|---|---|---|---|
| Arsenic | 2,371 | 460 | 866 |
| Chromium-6 | 534 | 91 | 217 |
| Copper | 19 | 14 | 483 |
| Lead | 1,868 | 364 | 1,517 |
| Nitrates | 996 | 210 | 584 |
| PFAS | 1,109 | 249 | 10,112 |
| Radon | 0 | 0 | 0 |
Open data, licensed CC BY 4.0 · DOI: 10.5281/zenodo.19427201
How we compute this
We aggregate EPA drinking-water violation records by contaminant type, using the one metric family defined uniformly across all seven contaminants: the violation count, the number of ZIP codes with a violation, and the number of ZIP codes affected. PFAS-specific monitoring fields are reported in separate PFAS findings, not blended here.
Contaminants are listed alphabetically, framed as a distribution rather than a ranking. A higher violation count reflects more recorded violations of that standard; it is not a causal claim about relative harm.
Counts recompute each build from the latest EPA extracts. Each affected ZIP code links to its per-ZIP report with the underlying records.
Frequently asked questions
Which contaminants cause the most drinking-water violations?
EPA logs 6,897 drinking-water violations across 7 regulated contaminants as of March 2026. ZipCheckup lists each contaminant alphabetically with its violation count and affected ZIP codes — a distribution, not a ranking. according to ZipCheckup's reading of federal data as of March 2026.
How many ZIP codes are affected by contaminant violations?
ZipCheckup tracks violation counts and affected ZIP codes for 7 contaminants — lead, copper, arsenic, nitrates, PFAS, chromium-6, and radon — as of March 2026. The per-contaminant table shows the affected-ZIP count for each.