Aldicarb in drinking water
347 active public water systems in 11 states had a Aldicarb violation in the past three years, and 10 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 Aldicarb and lists the water systems whose records include a related violation. It does not show measured levels.
Is Aldicarb 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
Aldicarb is a systemic carbamate insecticide and nematicide that was applied to potatoes, citrus, peanuts, soybeans, and other crops. It was one of the most acutely toxic pesticides registered in the US. Voluntarily canceled by its manufacturer in 2011, it has a legacy of groundwater contamination — it is highly water-soluble, mobile in soil, and has been found in wells across agricultural regions.
Health effects
Aldicarb is highly acutely toxic through acetylcholinesterase inhibition, disrupting nerve signal transmission at synapses. Symptoms of acute poisoning include excessive salivation, muscle tremors, nausea, convulsions, and at high doses respiratory arrest. Even short-term exposure above the MCL poses significant risk; children and the elderly are most vulnerable.
The standard and what a violation means
EPA limit: 0.003 mg/L (3 ppb).
Water systems with a Aldicarb 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 |
|---|---|---|---|
| New York | 119 | 1% | 1 |
| Texas | 102 | 1% | 0 |
| Connecticut | 35 | 1% | 1 |
| Michigan | 26 | 0% | 0 |
| Colorado | 21 | 1% | 1 |
| Missouri | 16 | 1% | 1 |
| Rhode Island | 10 | 2% | 0 |
| Illinois | 9 | 0% | 4 |
| New Jersey | 6 | 0% | 2 |
| Wisconsin | 2 | 0% | 0 |
| Kentucky | 1 | 0% | 0 |
Largest water systems with a Aldicarb 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 | |
|
Aqua WSC Bastrop County |
86,325 | 5 | 1 | |
|
South Huntington Water District Huntington (t) · Suffolk County |
81,760 | 1 | 0 | |
|
Johnson County SUD Johnson County |
65,517 | 2 | 0 | |
|
Kiryas Joel Kiryas Joel (v) · Orange County |
51,623 | 3 | 0 | |
|
Clwsc Canyon Lake Shores Comal County |
44,196 | 6 | 0 | |
|
City of Sherman Grayson County |
43,645 | 2 | 0 | |
|
Clifton Park Water Authority Clifton Park (t) · Saratoga County |
35,000 | 6 | 1 | |
|
Bethesda WSC Johnson County |
33,441 | 2 | 0 | |
|
West Bend Waterworks West Bend · Washington County |
32,149 | 5 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Aldicarb, including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Aldicarb 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.