Benzo(a)pyrene in drinking water
1,250 active public water systems in 37 states had a Benzo(a)pyrene violation in the past three years, and 61 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 Benzo(a)pyrene and lists the water systems whose records include a related violation. It does not show measured levels.
Is Benzo(a)pyrene 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.
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What it is and where it comes from
Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) formed during incomplete combustion of organic material. It enters drinking water primarily through leaching from coal tar linings in older water storage tanks and distribution pipes, as well as from contaminated soil and industrial runoff. It is one of the most studied PAHs due to its potent carcinogenicity.
Health effects
Benzo(a)pyrene is classified by EPA as a probable human carcinogen (Group B2) and is a well-established animal carcinogen. Long-term exposure is associated with increased cancer risk, particularly for reproductive organ cancers. It is also linked to immune system effects and developmental toxicity in animal studies.
The standard and what a violation means
EPA limit: 0.0002 mg/L (0.2 ppb).
Water systems with a Benzo(a)pyrene 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 | 200 | 3% | 8 |
| New York | 120 | 1% | 1 |
| Texas | 115 | 2% | 0 |
| Illinois | 107 | 2% | 11 |
| Oklahoma | 97 | 8% | 0 |
| Oregon | 85 | 3% | 3 |
| Washington | 44 | 1% | 8 |
| Colorado | 38 | 2% | 4 |
| Montana | 37 | 2% | 1 |
| Idaho | 36 | 2% | 3 |
| Connecticut | 34 | 1% | 1 |
| West Virginia | 33 | 4% | 4 |
| Utah | 29 | 3% | 1 |
| Michigan | 28 | 0% | 1 |
| Indiana | 27 | 1% | 2 |
| Alaska | 25 | 2% | 0 |
| Alabama | 25 | 4% | 0 |
| California | 25 | 0% | 1 |
| Wyoming | 24 | 3% | 1 |
| Vermont | 22 | 2% | 3 |
| Nevada | 17 | 3% | 0 |
| Arizona | 15 | 1% | 1 |
| North Carolina | 13 | 0% | 1 |
| Massachusetts | 12 | 1% | 1 |
| Minnesota | 9 | 0% | 2 |
| Rhode Island | 9 | 2% | 0 |
| New Jersey | 6 | 0% | 2 |
| Maryland | 3 | 0% | 1 |
| South Dakota | 3 | 0% | 0 |
| Wisconsin | 3 | 0% | 0 |
| North Dakota | 2 | 1% | 0 |
| New Mexico | 2 | 0% | 0 |
| Kentucky | 1 | 0% | 0 |
| Nebraska | 1 | 0% | 0 |
| New Hampshire | 1 | 0% | 0 |
| Ohio | 1 | 0% | 0 |
| Tennessee | 1 | 0% | 0 |
Largest water systems with a Benzo(a)pyrene 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 |
|---|---|---|---|---|
|
Denver Water Board Denver County |
1,287,000 | 3 | 0 | |
|
Pittsburgh Water & Sewer Auth Allegheny County |
520,000 | 3 | 0 | |
|
Gilbert, Town of Gilbert · Maricopa County |
247,600 | 9 | 1 | |
|
Corona, City of Corona · Riverside County |
169,380 | 6 | 0 | |
|
City of Sunnyvale Sunnyvale · Santa Clara County |
157,566 | 5 | 0 | |
|
Naperville Naperville · DuPage County |
156,406 | 1 | 0 | |
|
Epcor Agua Fria Surprise · Maricopa County |
128,040 | 5 | 0 | |
|
Pasco Water Department Franklin County |
115,102 | 2 | 0 | |
|
Inima USA / Aquaria LLC Dighton · Bristol County |
105,643 | 1 | 0 | |
|
Lehi City Utah County |
93,446 | 2 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Benzo(a)pyrene, including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Benzo(a)pyrene 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.