Chromium in drinking water
851 active public water systems in 43 states had a Chromium violation in the past three years, and 15 have one that is still unresolved.
You are on Tapcensus, an independent guide to the EPA compliance records of every public water system in the United States. This page explains Chromium and lists the water systems whose records include a related violation. It does not show measured levels.
Is Chromium in the records for your water system?
Enter a ZIP code, town, or street address to see the water systems that serve your area, their status, and which rules and contaminants appear in their violations.
Enter a ZIP code, town, or street address.
What it is and where it comes from
Chromium occurs naturally in rocks, soil, and volcanic dust and enters drinking water through natural leaching from mineral deposits and industrial discharge from electroplating, leather tanning, and textile manufacturing. Hexavalent chromium (Cr(VI)) and trivalent chromium (Cr(III)) are the two main forms; both are regulated together under this MCL.
Health effects
Hexavalent chromium is associated with increased cancer risk through ingestion in animal studies and is classified by EPA as a probable human carcinogen (Group B1) for inhalation, with growing evidence for oral carcinogenicity. Chronic exposure to total chromium causes liver and kidney damage, allergic dermatitis, and gastrointestinal irritation. Individuals with pre-existing liver or kidney conditions face greater risk.
The standard and what a violation means
EPA limit: 0.1 mg/L (100 ppb) — total chromium.
Water systems with a Chromium violation, by state
Active public water systems that reported at least one related violation to EPA in the past three years. Each state links to the list of its affected systems.
| State | Systems with violations, 3 yr | Share of active systems | Unresolved |
|---|---|---|---|
| Pennsylvania | 120 | 2% | 0 |
| Texas | 74 | 1% | 1 |
| Illinois | 69 | 1% | 2 |
| Georgia | 61 | 3% | 0 |
| New York | 55 | 1% | 0 |
| Michigan | 48 | 0% | 0 |
| Colorado | 29 | 1% | 4 |
| Indiana | 29 | 1% | 0 |
| West Virginia | 28 | 4% | 0 |
| New Jersey | 25 | 1% | 0 |
| California | 23 | 0% | 0 |
| Wyoming | 22 | 3% | 0 |
| Missouri | 21 | 1% | 2 |
| Washington | 21 | 0% | 0 |
| Montana | 20 | 1% | 0 |
| Oklahoma | 20 | 2% | 0 |
| Idaho | 19 | 1% | 1 |
| Connecticut | 17 | 1% | 0 |
| Virginia | 15 | 1% | 0 |
| Oregon | 13 | 1% | 0 |
| Maine | 12 | 1% | 0 |
| Wisconsin | 11 | 0% | 0 |
| Massachusetts | 10 | 1% | 2 |
| Utah | 10 | 1% | 0 |
| Iowa | 8 | 0% | 0 |
| Nevada | 8 | 1% | 0 |
| Alaska | 7 | 1% | 0 |
| Mississippi | 7 | 1% | 0 |
| Vermont | 7 | 1% | 2 |
| Arizona | 6 | 0% | 1 |
| North Carolina | 6 | 0% | 0 |
| Maryland | 5 | 0% | 0 |
| Minnesota | 5 | 0% | 0 |
| Alabama | 4 | 1% | 0 |
| Rhode Island | 4 | 1% | 0 |
| Florida | 2 | 0% | 0 |
| Kansas | 2 | 0% | 0 |
| New Hampshire | 2 | 0% | 0 |
| South Dakota | 2 | 0% | 0 |
| Hawaii | 1 | 1% | 0 |
| Kentucky | 1 | 0% | 0 |
| North Dakota | 1 | 0% | 0 |
| New Mexico | 1 | 0% | 0 |
Largest water systems with a Chromium violation
The ten biggest systems, by people served, whose records include a related violation in the past three years.
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Aqua PA Main System Montgomery County |
822,600 | 6 | 0 | |
|
Aquarion-Eastern Fairfield County Beacon Falls, Bridgeport, Darien and 17 more · Fairfield County |
351,756 | 2 | 0 | |
|
Corona, City of Corona · Riverside County |
169,380 | 6 | 0 | |
|
City of Sunnyvale Sunnyvale · Santa Clara County |
157,566 | 5 | 0 | |
|
Aqua WSC Bastrop County |
86,325 | 5 | 1 | |
|
GW Santa Cruz Water CO Maricopa · Pinal County |
84,000 | 7 | 0 | |
|
Tigard, City of Washington County |
62,500 | 2 | 0 | |
|
Greater Johnstown WA Riverside Cambria County |
49,500 | 7 | 0 | |
|
Greenlawn Water District Huntington (t) · Suffolk County |
42,000 | 3 | 0 | |
|
Winslow Twp Dmu Winslow Twp · Camden County |
39,174 | 6 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Chromium, including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Chromium alone. Counts cover active systems in all 50 states and the District of Columbia.
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 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.