Pentachlorophenol in drinking water
1,180 active public water systems in 39 states had a Pentachlorophenol violation in the past three years, and 56 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 Pentachlorophenol and lists the water systems whose records include a related violation. It does not show measured levels.
Is Pentachlorophenol 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
Pentachlorophenol (PCP) is a chlorinated phenol used as a wood preservative, primarily for utility poles, railroad ties, and fence posts. It remains in limited industrial use in the United States. PCP leaches from treated wood into surrounding soil and groundwater, and can enter surface water through runoff from treated wood storage sites.
Health effects
Chronic exposure to pentachlorophenol is associated with liver and kidney damage and immune system effects. EPA classifies it as a probable human carcinogen (Group B2). Acute high-level exposure can cause fever, profuse sweating, and cardiovascular collapse. Workers and communities near wood treatment facilities face the greatest exposure risk.
The standard and what a violation means
EPA limit: 0.001 mg/L (1 ppb).
Water systems with a Pentachlorophenol 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 | 200 | 3% | 7 |
| New York | 119 | 1% | 1 |
| Texas | 115 | 2% | 0 |
| Oklahoma | 96 | 7% | 0 |
| Oregon | 72 | 3% | 3 |
| Washington | 44 | 1% | 9 |
| Illinois | 41 | 1% | 10 |
| Colorado | 37 | 2% | 4 |
| Montana | 37 | 2% | 1 |
| Idaho | 36 | 2% | 3 |
| Connecticut | 30 | 1% | 1 |
| Utah | 29 | 3% | 1 |
| California | 28 | 0% | 1 |
| Indiana | 27 | 1% | 2 |
| Michigan | 26 | 0% | 0 |
| Alaska | 25 | 2% | 0 |
| Alabama | 25 | 4% | 0 |
| Wyoming | 24 | 3% | 1 |
| Vermont | 22 | 2% | 3 |
| Missouri | 19 | 1% | 1 |
| Wisconsin | 19 | 0% | 0 |
| Nevada | 17 | 3% | 0 |
| Arizona | 15 | 1% | 2 |
| Iowa | 15 | 1% | 0 |
| Massachusetts | 13 | 1% | 1 |
| North Carolina | 8 | 0% | 1 |
| Rhode Island | 8 | 2% | 0 |
| Maine | 6 | 0% | 0 |
| Minnesota | 6 | 0% | 2 |
| New Jersey | 6 | 0% | 2 |
| 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 Pentachlorophenol 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 | |
|
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 | |
|
Lehi City Utah County |
93,446 | 2 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Pentachlorophenol, including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Pentachlorophenol 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.