Chlordane in drinking water
1,210 active public water systems in 38 states had a Chlordane violation in the past three years, and 58 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 Chlordane and lists the water systems whose records include a related violation. It does not show measured levels.
Is Chlordane 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
Chlordane is a broad-spectrum organochlorine insecticide used extensively for termite control and on crops including corn and citrus. All uses were banned in the United States in 1988. Chlordane is extremely persistent in soil and can leach slowly into groundwater over decades. Legacy contamination is most prevalent in areas with intensive historical use.
Health effects
Chronic chlordane exposure is associated with liver damage and increased cancer risk. EPA classifies it as a probable human carcinogen (Group B2). Animal studies show liver tumors at elevated doses. It bioaccumulates in fatty tissue and can be passed to infants through breast milk. Children and immunocompromised individuals are most vulnerable.
The standard and what a violation means
EPA limit: 0.002 mg/L (2 ppb).
Water systems with a Chlordane 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 | 183 | 2% | 7 |
| New York | 120 | 1% | 1 |
| Texas | 115 | 2% | 0 |
| Oklahoma | 97 | 8% | 0 |
| Oregon | 73 | 3% | 3 |
| Illinois | 57 | 1% | 9 |
| Washington | 44 | 1% | 8 |
| Colorado | 39 | 2% | 4 |
| Idaho | 38 | 2% | 3 |
| Montana | 37 | 2% | 1 |
| Connecticut | 30 | 1% | 1 |
| Michigan | 29 | 0% | 1 |
| Utah | 29 | 3% | 1 |
| West Virginia | 29 | 4% | 2 |
| Indiana | 27 | 1% | 2 |
| California | 26 | 0% | 1 |
| Alaska | 25 | 2% | 0 |
| Alabama | 25 | 4% | 0 |
| Wyoming | 24 | 3% | 1 |
| Vermont | 22 | 2% | 3 |
| Wisconsin | 18 | 0% | 0 |
| Missouri | 16 | 1% | 1 |
| Nevada | 16 | 3% | 0 |
| North Carolina | 14 | 0% | 1 |
| Arizona | 13 | 1% | 1 |
| Massachusetts | 12 | 1% | 1 |
| Minnesota | 9 | 0% | 2 |
| New Jersey | 9 | 0% | 2 |
| Rhode Island | 9 | 2% | 0 |
| Maine | 8 | 0% | 0 |
| Maryland | 4 | 0% | 2 |
| South Dakota | 3 | 0% | 0 |
| Virginia | 3 | 0% | 0 |
| North Dakota | 2 | 1% | 0 |
| New Mexico | 2 | 0% | 0 |
| Kentucky | 1 | 0% | 0 |
| New Hampshire | 1 | 0% | 0 |
| Tennessee | 1 | 0% | 0 |
Largest water systems with a Chlordane 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 | |
|
Rockford Rockford · Winnebago County |
147,051 | 3 | 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 |
About this data
A system is counted once if any of its violations in the past three years involved Chlordane, including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Chlordane 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.