Total Haloacetic Acids (HAA5) in drinking water
5,721 active public water systems in 50 states had a Total Haloacetic Acids (HAA5) violation in the past three years, and 486 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 Total Haloacetic Acids (HAA5) and lists the water systems whose records include a related violation. It does not show measured levels.
Is Total Haloacetic Acids (HAA5) 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
HAA5 are five haloacetic acids formed when chlorine disinfectants react with naturally occurring organic matter in source water. Higher levels occur with more organic-rich source water or when water sits longer in distribution pipes. The violation indicates the locational running annual average exceeded the MCL.
Health effects
Dichloroacetic acid is a probable human carcinogen (Group B2). Long-term exposure to trichloroacetic acid may also increase cancer risk. Animal studies show liver, kidney, and reproductive effects at high doses.
The standard and what a violation means
EPA limit: 0.060 mg/L (60 ppb) locational running annual average (LRAA).
Water systems with a Total Haloacetic Acids (HAA5) 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 | 505 | 7% | 32 |
| Mississippi | 490 | 41% | 10 |
| Florida | 470 | 9% | 8 |
| Illinois | 382 | 7% | 48 |
| Oklahoma | 282 | 22% | 68 |
| Texas | 262 | 4% | 36 |
| North Carolina | 253 | 5% | 28 |
| New York | 218 | 3% | 3 |
| Arizona | 213 | 12% | 18 |
| Washington | 200 | 4% | 13 |
| Colorado | 189 | 9% | 10 |
| Kansas | 143 | 15% | 11 |
| West Virginia | 136 | 18% | 28 |
| Oregon | 133 | 5% | 4 |
| California | 122 | 2% | 6 |
| Alaska | 118 | 9% | 27 |
| Michigan | 117 | 1% | 9 |
| Virginia | 112 | 4% | 12 |
| Ohio | 100 | 2% | 1 |
| Missouri | 98 | 3% | 10 |
| Indiana | 92 | 2% | 4 |
| Montana | 89 | 4% | 3 |
| New Jersey | 82 | 2% | 8 |
| Iowa | 71 | 4% | 1 |
| Vermont | 64 | 5% | 8 |
| Tennessee | 61 | 8% | 3 |
| Georgia | 60 | 3% | 9 |
| Idaho | 60 | 3% | 6 |
| Alabama | 57 | 10% | 4 |
| Utah | 57 | 5% | 1 |
| Wisconsin | 55 | 0% | 1 |
| Kentucky | 45 | 11% | 13 |
| New Hampshire | 41 | 2% | 10 |
| New Mexico | 39 | 3% | 4 |
| Louisiana | 34 | 3% | 16 |
| Massachusetts | 33 | 2% | 2 |
| Wyoming | 33 | 4% | 2 |
| Maryland | 32 | 1% | 0 |
| South Dakota | 31 | 4% | 0 |
| Nevada | 30 | 5% | 1 |
| Maine | 28 | 1% | 0 |
| Connecticut | 19 | 1% | 2 |
| Arkansas | 12 | 1% | 0 |
| North Dakota | 12 | 3% | 2 |
| Rhode Island | 12 | 3% | 0 |
| Minnesota | 11 | 0% | 2 |
| South Carolina | 11 | 1% | 2 |
| District of Columbia | 4 | 29% | 0 |
| Nebraska | 2 | 0% | 0 |
| Hawaii | 1 | 1% | 0 |
Largest water systems with a Total Haloacetic Acids (HAA5) 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 |
|---|---|---|---|---|
|
Mdwasa Main System Miami · Miami-Dade County |
2,377,460 | 2 | 0 | |
|
Central Alabama Water Birmingham · Jefferson County |
653,322 | 2 | 1 | |
|
Pittsburgh Water & Sewer Auth Allegheny County |
520,000 | 3 | 0 | |
|
Pinellas County Utilities Clearwater · Pinellas County |
506,353 | 4 | 0 | |
|
City of Anaheim Anaheim · Orange County |
350,254 | 1 | 0 | |
|
ST Petersburg, City of Odessa · Pinellas County |
349,979 | 4 | 0 | |
|
Manatee County Utilities Dept Bradenton · Manatee County |
347,800 | 2 | 0 | |
|
Passaic Valley Water Commission Little Falls Twp · Passaic County |
310,483 | 3 | 0 | |
|
Lee County Utilities Fort Myers · Lee County |
282,556 | 1 | 0 | |
|
Akron City PWS Summit County |
280,000 | 1 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Total Haloacetic Acids (HAA5), including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Total Haloacetic Acids (HAA5) 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.