2,4-D in drinking water
1,205 active public water systems in 40 states had a 2,4-D violation in the past three years, and 51 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 2,4-D and lists the water systems whose records include a related violation. It does not show measured levels.
Is 2,4-D 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
2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most widely used herbicides in the world, applied to lawns, turf, pastures, and crops to control broadleaf weeds. It remains in active use in the United States. 2,4-D is water-soluble and can enter drinking water through agricultural and residential runoff and leaching into groundwater.
Health effects
Chronic exposure to 2,4-D is associated with kidney, liver, and adrenal gland damage in animal studies. IARC classifies it as possibly carcinogenic to humans (Group 2B); EPA's classification is not likely to be carcinogenic under current guidelines. Individuals with kidney or liver conditions may face greater risk from long-term exposure.
The standard and what a violation means
EPA limit: 0.07 mg/L (70 ppb).
Water systems with a 2,4-D 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 | 206 | 3% | 8 |
| Oklahoma | 131 | 10% | 0 |
| New York | 119 | 1% | 1 |
| Oregon | 84 | 3% | 3 |
| Texas | 84 | 1% | 0 |
| Illinois | 40 | 1% | 10 |
| Colorado | 38 | 2% | 4 |
| Idaho | 37 | 2% | 3 |
| Montana | 37 | 2% | 1 |
| West Virginia | 34 | 4% | 3 |
| Connecticut | 30 | 1% | 1 |
| Indiana | 29 | 1% | 2 |
| Utah | 29 | 3% | 1 |
| Alabama | 28 | 5% | 0 |
| California | 28 | 0% | 1 |
| Michigan | 26 | 0% | 0 |
| Alaska | 25 | 2% | 0 |
| Wyoming | 24 | 3% | 1 |
| Vermont | 22 | 2% | 3 |
| Missouri | 19 | 1% | 1 |
| Wisconsin | 18 | 0% | 0 |
| Arizona | 17 | 1% | 1 |
| Nevada | 16 | 3% | 0 |
| Iowa | 14 | 1% | 0 |
| Massachusetts | 13 | 1% | 1 |
| New Jersey | 9 | 0% | 3 |
| North Carolina | 8 | 0% | 1 |
| Rhode Island | 8 | 2% | 0 |
| Maine | 6 | 0% | 0 |
| Minnesota | 6 | 0% | 2 |
| Washington | 5 | 0% | 0 |
| South Dakota | 3 | 0% | 0 |
| Virginia | 3 | 0% | 0 |
| North Dakota | 2 | 1% | 0 |
| New Mexico | 2 | 0% | 0 |
| Florida | 1 | 0% | 0 |
| Kentucky | 1 | 0% | 0 |
| New Hampshire | 1 | 0% | 0 |
| Ohio | 1 | 0% | 0 |
| Tennessee | 1 | 0% | 0 |
Largest water systems with a 2,4-D 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 | |
|
Passaic Valley Water Commission Little Falls Twp · Passaic County |
310,483 | 3 | 0 | |
|
Gilbert, Town of Gilbert · Maricopa County |
247,600 | 9 | 1 | |
|
Scottsdale City of Scottsdale · Maricopa County |
241,361 | 2 | 0 | |
|
Corona, City of Corona · Riverside County |
169,380 | 6 | 0 | |
|
City of Sunnyvale Sunnyvale · Santa Clara County |
157,566 | 5 | 0 | |
|
Rockford Rockford · Winnebago County |
147,051 | 3 | 0 | |
|
Epcor Agua Fria Surprise · Maricopa County |
128,040 | 5 | 0 | |
|
Inima USA / Aquaria LLC Dighton · Bristol County |
105,643 | 1 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved 2,4-D, including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not 2,4-D 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.