Toluene in drinking water
1,958 active public water systems in 42 states had a Toluene violation in the past three years, and 88 had one in the latest quarter of EPA's data.
You are on Tapcensus, an independent guide to the EPA compliance records of every public water system in the United States. This page explains Toluene and lists the water systems whose records include a related violation. It does not show measured levels.
Is Toluene 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
Toluene is an aromatic hydrocarbon solvent found in gasoline, paints, adhesives, and chemical manufacturing. It is a BTEX compound (benzene, toluene, ethylbenzene, xylene) and enters drinking water through leaking underground fuel storage tanks, petroleum spills, and industrial discharge. It is highly volatile but can persist in groundwater at contamination sites.
Health effects
Short-term exposure above the MCL can cause nervous system effects including headache, dizziness, and impaired coordination. Chronic exposure is associated with kidney and liver damage and neurological effects. EPA has not classified toluene as a human carcinogen. Developing fetuses may be particularly sensitive to its neurotoxic effects.
The standard and what a violation means
EPA limit: 1 mg/L (1,000 ppb).
Water systems with a Toluene 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 | In violation, latest quarter |
|---|---|---|---|
| Illinois | 198 | 4% | 11 |
| Texas | 171 | 2% | 0 |
| Pennsylvania | 170 | 2% | 6 |
| Michigan | 165 | 1% | 4 |
| Washington | 103 | 2% | 10 |
| Alaska | 101 | 8% | 5 |
| Oregon | 88 | 3% | 3 |
| New Jersey | 76 | 2% | 5 |
| New York | 75 | 1% | 2 |
| Colorado | 72 | 3% | 4 |
| Oklahoma | 71 | 5% | 0 |
| Indiana | 66 | 2% | 3 |
| Idaho | 49 | 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 |
| Wyoming | 33 | 4% | 2 |
| Virginia | 31 | 1% | 2 |
| California | 30 | 0% | 2 |
| Vermont | 30 | 2% | 3 |
| Utah | 27 | 3% | 1 |
| North Carolina | 26 | 1% | 1 |
| Nevada | 26 | 4% | 0 |
| Alabama | 18 | 3% | 0 |
| Maine | 18 | 1% | 0 |
| Ohio | 14 | 0% | 1 |
| Iowa | 13 | 1% | 0 |
| Massachusetts | 12 | 1% | 0 |
| Tennessee | 11 | 1% | 0 |
| Rhode Island | 9 | 2% | 1 |
| Minnesota | 7 | 0% | 1 |
| New Hampshire | 4 | 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 Toluene 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 Toluene, including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Toluene 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.