Dichloromethane (Methylene Chloride) in drinking water
1,958 active public water systems in 42 states had a Dichloromethane (Methylene Chloride) violation in the past three years, and 86 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 Dichloromethane (Methylene Chloride) and lists the water systems whose records include a related violation. It does not show measured levels.
Is Dichloromethane (Methylene Chloride) 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
Dichloromethane (DCM), also called methylene chloride, is a widely used industrial solvent employed in paint stripping, pharmaceutical manufacturing, and metal degreasing. It enters drinking water through industrial discharge and improper disposal. It is volatile and evaporates quickly from open water but can persist in groundwater.
Health effects
Chronic exposure to dichloromethane is associated with liver and kidney damage and neurological effects. EPA classifies it as a probable human carcinogen (Group B2); it is metabolized in the body to carbon monoxide and has been linked to cardiovascular stress. Workers in industrial settings and communities near manufacturing sites face the greatest risk.
The standard and what a violation means
EPA limit: 0.005 mg/L (5 ppb).
Water systems with a Dichloromethane (Methylene Chloride) 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 | 195 | 4% | 10 |
| Pennsylvania | 173 | 2% | 6 |
| Texas | 171 | 2% | 0 |
| Michigan | 165 | 1% | 4 |
| Alaska | 102 | 8% | 5 |
| Washington | 102 | 2% | 10 |
| Oregon | 85 | 3% | 3 |
| New Jersey | 77 | 2% | 5 |
| New York | 73 | 1% | 2 |
| Oklahoma | 71 | 5% | 0 |
| Colorado | 69 | 3% | 4 |
| Indiana | 66 | 2% | 3 |
| Idaho | 48 | 2% | 3 |
| Wisconsin | 46 | 0% | 5 |
| Connecticut | 42 | 2% | 4 |
| Montana | 41 | 2% | 0 |
| West Virginia | 38 | 5% | 1 |
| Arizona | 35 | 2% | 3 |
| Missouri | 34 | 1% | 2 |
| Wyoming | 32 | 4% | 1 |
| Virginia | 31 | 1% | 2 |
| Vermont | 30 | 2% | 3 |
| California | 29 | 0% | 2 |
| Nevada | 27 | 4% | 0 |
| North Carolina | 26 | 1% | 1 |
| Utah | 26 | 2% | 1 |
| Maine | 19 | 1% | 0 |
| Alabama | 18 | 3% | 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 Dichloromethane (Methylene Chloride) 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 Dichloromethane (Methylene Chloride), including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Dichloromethane (Methylene Chloride) 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.