2,4,5-TP (Silvex) in drinking water
1,175 active public water systems in 36 states had a 2,4,5-TP (Silvex) violation in the past three years, and 55 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 2,4,5-TP (Silvex) and lists the water systems whose records include a related violation. It does not show measured levels.
Is 2,4,5-TP (Silvex) 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
Silvex (2,4,5-trichlorophenoxypropionic acid) was a chlorophenoxy herbicide used to control woody plants and broadleaf weeds on cropland, orchards, and roadsides. All uses were canceled in the United States in 1985 due to contamination with dioxin (TCDD) during manufacture. Legacy residues persist in agricultural soils and can leach into groundwater.
Health effects
Chronic exposure to Silvex is associated with liver damage. EPA classifies it as a possible human carcinogen (Group C). The dioxin contamination historically associated with its production added to concern about its carcinogenicity, though the MCL applies to Silvex itself. Long-term exposure above the MCL is the primary concern.
The standard and what a violation means
EPA limit: 0.05 mg/L (50 ppb).
Water systems with a 2,4,5-TP (Silvex) 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 | 248 | 3% | 7 |
| New York | 119 | 1% | 1 |
| Oklahoma | 95 | 7% | 0 |
| Texas | 84 | 1% | 0 |
| Oregon | 72 | 3% | 3 |
| Washington | 44 | 1% | 9 |
| Illinois | 40 | 1% | 10 |
| Idaho | 38 | 2% | 3 |
| Colorado | 37 | 2% | 4 |
| Montana | 37 | 2% | 1 |
| 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 | 18 | 0% | 0 |
| Nevada | 16 | 3% | 0 |
| Arizona | 13 | 1% | 1 |
| Massachusetts | 12 | 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 |
Largest water systems with a 2,4,5-TP (Silvex) 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 2,4,5-TP (Silvex), including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not 2,4,5-TP (Silvex) 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.