Benzene in drinking water
2,000 active public water systems in 42 states had a Benzene violation in the past three years, and 87 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 Benzene and lists the water systems whose records include a related violation. It does not show measured levels.
Is Benzene 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
Benzene is a fundamental aromatic hydrocarbon and component of crude oil, gasoline, and many industrial chemicals. It enters drinking water primarily through leaking underground fuel storage tanks, industrial discharge, and contaminated runoff. It is one of the most commonly detected VOCs at Superfund sites and underground storage tank cleanup sites across the United States.
Health effects
Benzene is classified by EPA as a known human carcinogen (Group A). Long-term exposure causes leukemia, particularly acute myeloid leukemia (AML), and other blood disorders including aplastic anemia. There is no established safe threshold. Children and individuals with compromised immune systems are most vulnerable to hematological effects.
The standard and what a violation means
EPA limit: 0.005 mg/L (5 ppb).
Water systems with a Benzene 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 |
|---|---|---|---|
| Illinois | 197 | 4% | 11 |
| Texas | 173 | 2% | 0 |
| Pennsylvania | 169 | 2% | 6 |
| Michigan | 165 | 1% | 4 |
| New York | 126 | 2% | 2 |
| Washington | 102 | 2% | 10 |
| Alaska | 101 | 8% | 5 |
| Oregon | 85 | 3% | 3 |
| New Jersey | 77 | 2% | 5 |
| Oklahoma | 71 | 5% | 0 |
| Colorado | 69 | 3% | 4 |
| Indiana | 66 | 2% | 3 |
| Idaho | 48 | 2% | 3 |
| Wisconsin | 45 | 0% | 5 |
| Montana | 40 | 2% | 0 |
| Connecticut | 39 | 2% | 4 |
| West Virginia | 38 | 5% | 1 |
| Missouri | 34 | 1% | 2 |
| Arizona | 33 | 2% | 3 |
| Virginia | 31 | 1% | 2 |
| Wyoming | 31 | 4% | 1 |
| Vermont | 30 | 2% | 3 |
| California | 29 | 0% | 2 |
| North Carolina | 26 | 1% | 1 |
| Nevada | 26 | 4% | 0 |
| Utah | 26 | 2% | 1 |
| Alabama | 18 | 3% | 0 |
| Maine | 18 | 1% | 0 |
| Iowa | 14 | 1% | 0 |
| Ohio | 14 | 0% | 1 |
| Massachusetts | 12 | 1% | 0 |
| Tennessee | 11 | 1% | 0 |
| Rhode Island | 9 | 2% | 1 |
| Minnesota | 7 | 0% | 1 |
| New Hampshire | 5 | 0% | 1 |
| Kansas | 3 | 0% | 0 |
| Mississippi | 3 | 0% | 1 |
| New Mexico | 3 | 0% | 0 |
| Maryland | 2 | 0% | 0 |
| South Dakota | 2 | 0% | 0 |
| Kentucky | 1 | 0% | 0 |
| North Dakota | 1 | 0% | 1 |
Largest water systems with a Benzene 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 |
|---|---|---|---|---|
|
Tucson City of Tucson · Pima County |
732,906 | 3 | 0 | |
|
Mesa City of Mesa · Maricopa County |
466,000 | 3 | 0 | |
|
Chandler City of Chandler · Maricopa County |
247,328 | 4 | 0 | |
|
Trenton Water Works Ewing Twp, Hamilton Twp, Hopewell Twp.1106- and 2 more · Mercer County |
217,000 | 8 | 2 | |
|
Corona, City of Corona · Riverside County |
169,380 | 6 | 0 | |
|
City of Sunnyvale Sunnyvale · Santa Clara County |
157,566 | 5 | 0 | |
|
Sandy City Water System Salt Lake County |
99,750 | 2 | 0 | |
|
Epcor San Tan Johnson Ranch · Pinal County |
87,435 | 3 | 0 | |
|
Flagstaff City of Flagstaff · Coconino County |
79,796 | 5 | 0 | |
|
East Orange Water Commission East Orange City · Essex County |
75,000 | 6 | 1 |
About this data
A system is counted once if any of its violations in the past three years involved Benzene, including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Benzene 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.