Total Haloacetic Acids (HAA5) in U.S. Drinking Water
Health-based violation data for Total Haloacetic Acids (HAA5) from EPA Safe Drinking Water Information System (SDWIS). Covers all community water systems with violations on record.
Total Haloacetic Acids (HAA5) has been found in violation of EPA standards in 1,857 water systems across 49 states, with 25,028 total health-based violations recorded. The most affected states are Oklahoma, Louisiana, Texas.
Total Haloacetic Acids (HAA5) is regulated under the EPA Safe Drinking Water Act, which sets enforceable Maximum Contaminant Levels (MCLs) and associated treatment technique requirements for public water systems. The EPA Safe Drinking Water Information System (SDWIS) tracks every recorded violation nationwide and links it back to the specific public water system (PWSID), violation type, and begin date.
Across the United States, PlainEnviro's joined extract contains 25,028 health-based violation records carrying Total Haloacetic Acids (HAA5) (EPA code 2456) across 1,857 active community water systems in 49 states. Raw record counts are highest in Oklahoma, Louisiana, Texas, with Oklahoma accounting for 4,759 records across 184 systems. EPA health-effect summaries describe the specific exposure concerns that drove the federal standard.
A health-based violation does not mean residents were necessarily harmed, it means the contaminant exceeded the federal MCL in a compliance sample, triggering notification and remediation requirements. States and utilities maintain primary enforcement responsibility. To check the status of a specific water system, request its most recent Consumer Confidence Report or consult the EPA's Drinking Water Watch portal for the corresponding state.
What are the health effects of this contaminant?
Haloacetic acids are disinfection byproducts that form when chlorine reacts with natural organic matter. Long-term exposure is linked to increased cancer risk.
Source: U.S. Environmental Protection Agency. Consult your doctor for personalized health guidance
Violations by State
States ranked by number of health-based violations for Total Haloacetic Acids (HAA5).
| # | State | Violations | Systems Affected |
|---|---|---|---|
| 1 | Oklahoma | 4,759 | 184 |
| 2 | Louisiana | 2,383 | 85 |
| 3 | Texas | 2,294 | 153 |
| 4 | Pennsylvania | 1,216 | 58 |
| 5 | California | 1,208 | 92 |
| 6 | Alaska | 936 | 35 |
| 7 | Kentucky | 794 | 113 |
| 8 | Georgia | 711 | 34 |
| 9 | Kansas | 638 | 83 |
| 10 | New York | 606 | 62 |
| 11 | Florida | 602 | 68 |
| 12 | West Virginia | 580 | 66 |
| 13 | North Carolina | 544 | 50 |
| 14 | Tennessee | 478 | 43 |
| 15 | Puerto Rico | 430 | 47 |
| 16 | Virginia | 425 | 47 |
| 17 | Indiana | 341 | 30 |
| 18 | New Mexico | 307 | 11 |
| 19 | Missouri | 285 | 29 |
| 20 | Mississippi | 268 | 24 |
| 21 | Colorado | 262 | 17 |
| 22 | Arkansas | 252 | 27 |
| 23 | Oregon | 251 | 18 |
| 24 | Washington | 228 | 17 |
| 25 | Illinois | 223 | 28 |
| 26 | Maine | 191 | 11 |
| 27 | New Hampshire | 174 | 13 |
| 28 | Alabama | 148 | 15 |
| 29 | Montana | 135 | 16 |
| 30 | Idaho | 116 | 11 |
| 31 | Massachusetts | 115 | 11 |
| 32 | Ohio | 97 | 13 |
| 33 | Wyoming | 96 | 6 |
| 34 | Michigan | 58 | 7 |
| 35 | New Jersey | 51 | 11 |
| 36 | Vermont | 49 | 12 |
| 37 | Nevada | 48 | 1 |
| 38 | Maryland | 44 | 9 |
| 39 | South Carolina | 37 | 11 |
| 40 | Utah | 26 | 1 |
| 41 | Minnesota | 24 | 5 |
| 42 | American Samoa | 21 | 1 |
| 43 | Arizona | 13 | 3 |
| 44 | Iowa | 12 | 3 |
| 45 | North Dakota | 9 | 2 |
| 46 | Wisconsin | 9 | 3 |
| 47 | Connecticut | 5 | 3 |
| 48 | Nebraska | 4 | 1 |
| 49 | South Dakota | 1 | 1 |
Most Affected Water Systems
Top 50 water systems by number of Total Haloacetic Acids (HAA5) health-based violations.
Frequently Asked Questions
Is Total Haloacetic Acids (HAA5) in my water?
Total Haloacetic Acids (HAA5) has been detected in violation of EPA health standards in 1,857 water systems across 49 states. To check your specific utility, look up your annual Consumer Confidence Report (CCR) - water systems are required to disclose all violations.
How many water systems have Total Haloacetic Acids (HAA5) violations?
EPA SDWIS records show 1,857 community water systems with health-based Total Haloacetic Acids (HAA5) violations, totaling 25,028 violations. These represent cases where the contaminant exceeded the EPA Maximum Contaminant Level (MCL).
Which states have the most Total Haloacetic Acids (HAA5) violations?
The states with the most Total Haloacetic Acids (HAA5) violations are: Oklahoma (4,759 violations), Louisiana (2,383 violations), Texas (2,294 violations), Pennsylvania (1,216 violations), California (1,208 violations).
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About This Data
Violation data is from the EPA Safe Drinking Water Information System (SDWIS). Only health-based violations are shown, these include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations. Monitoring and reporting violations are excluded. Data may not reflect the most current enforcement actions.
Source: U.S. Environmental Protection Agency, SDWIS Federal Reporting Services
Read our methodology - how this data is sourced, computed, and verified.