Texas Tap Water Quality in 2026: Grades, Top Concerns and EPA Records

Texas tap water from large utilities generally meets federal legal limits, but it grades below the national average on our site. Of the 76 large Texas water systems we grade, none earned an A, 7 earned a B, and 36 (47%) were rated D or F. The average Texas score is 64 out of 100, compared with 68 across all 1,000 systems we track. The most common concern is disinfection byproducts. On the legal side, 43 of the 76 systems (57%) had at least one EPA violation in the last three years, and 12 (16%) had a health-based violation listed.

Below is what drives those grades, which systems had health-based violations, and how to check your own water.

What this data covers

TapWaterSafety.org grades 1,000 public water systems that each serve more than 50,000 people. Seventy-six are in Texas, serving about 18.2 million people combined. Texas has far more systems than that. The Texas Commission on Environmental Quality (TCEQ), which runs the state’s drinking water program under the federal Safe Drinking Water Act, reported 7,300 public water systems in its 2024 annual compliance report. Most are small, and they are not in this data.

Source: EPA ECHO compliance records, checked October 7, 2026; last 12 quarters. Contaminant concerns come from the EWG-based contaminant data used for our grades.

How grades work

Our grades are not a pass/fail on legal limits. Under our methodology, each system gets a 0 to 100 score from five weighted parts:

• Health guideline performance (40%): detected contaminant levels compared with EWG’s health-based guidelines, which are usually much stricter than EPA’s legal limits.
• Legal compliance (20%): health-based Safe Drinking Water Act violations in the last three years.
• High-risk contaminant presence (20%): whether contaminants such as PFAS, arsenic or lead are detected at all.
• Reporting history (10%): monitoring, reporting and public notice violations.
• Source water vulnerability (10%).

Scores of 85 and up are an A, 75 to 84 a B, 65 to 74 a C, 55 to 64 a D, and below 55 an F. A D or F usually means contaminants were detected well above health guidelines. It does not, by itself, mean the water breaks the law.

Texas grades at a glance

The largest system in the state, the City of Houston (about 2.97 million people), is graded D (57). The San Antonio Water System (about 2.11 million) has a B (75), the highest grade among Texas’s ten largest systems.

The ten largest Texas systems

The highest-scoring Texas systems are the City of Bryan (B, 80) and the City of Denton (B, 79). The lowest are the City of Midland Water Purification Plant (F, 44) and the City of Edinburg (F, 49).

The most common concerns in Texas

Each system page lists its top three concerns. Across the 76 Texas systems:

• Haloacetic acids (HAA9) above EWG’s health guideline: 72 systems
• Bromochloroacetic acid, one of the haloacetic acids: 42 systems
• Total trihalomethanes (TTHMs): 35 systems
• PFAS: 26 systems, including 19 where PFHxS is listed above the health guideline
• Arsenic: 22 systems

Disinfection byproducts dominate. Haloacetic acids and trihalomethanes form when chlorine or other disinfectants react with natural organic matter in water. Disinfection is essential because it kills germs, so the goal is to control byproducts, not to stop disinfecting. Texas relies heavily on surface water: 71 of the 76 systems in our data are listed as using surface water, directly or bought from another utility. Surface water usually carries more organic matter than groundwater. EPA’s legal limits are 80 parts per billion (ppb) for TTHMs and 60 ppb for five haloacetic acids (HAA5), as a running annual average. EWG’s health guidelines are far lower, which is why many systems that meet the law still show these concerns. Our guide to disinfection byproducts explains the difference.

Arsenic is largely natural. USGS studies of the Gulf Coast aquifer in the Houston area found that groundwater conditions there can release arsenic and radionuclides from aquifer materials. The Texas Water Development Board describes the southern part of the Ogallala aquifer as having naturally high levels of arsenic, radionuclides and fluoride. EPA’s legal limit for arsenic is 10 ppb, with a health goal of zero. See our arsenic guide.

PFAS showed up in some of the biggest systems, including Dallas, Austin, Fort Worth, El Paso and Houston’s neighbor, the City of Pasadena. For national context, see PFAS in large US water systems.

EPA violations in Texas

Over the last 12 quarters:

Most Texas violations are about paperwork, not water quality. Of the 87 violation entries in Texas systems’ records, 14 are health-based. The rest are monitoring, reporting, public notice and Consumer Confidence Report violations. A monitoring violation means a required test was missed or late. It is not a finding that the water was contaminated.

The five systems in violation every quarter were the City of Temple, Mustang SUD, the City of Odessa, Southern Utilities and the City of Pflugerville. Each has at least one long-running monitoring, reporting or public notice violation still listed as open, such as Temple’s public notice violation dating to November 2015.

The 12 systems with a health-based violation

Health-based means EPA recorded a maximum contaminant level (MCL) or treatment technique (TT) violation. Most of these are now listed as closed.

“Disinfection byproducts” here means the Stage 2 Disinfectants and Disinfection Byproducts Rule. “Surface water treatment” means the Interim and Long Term 1 Enhanced Surface Water Treatment Rule, which covers filtration performance. Under the Revised Total Coliform Rule, the only MCL is for E. coli. Our guide to coliform and E. coli in tap water explains what that type of violation means.

Six of the 12 are disinfection byproduct violations, which fits the concern data above.

How Texas compares

In our state rankings, Texas ranks 11th of 29 states by share of systems with any violation. It has the most systems with a health-based violation of any state (12), partly because it has many systems in our data. By comparison, only 10% of large California systems had any violation.

What Texas residents can do

1. Look up your system. Use our search page or the Texas state page to see your utility’s grade, top concerns and EPA record.
2. Check the violation type and status. A closed monitoring violation is very different from an open MCL violation.
3. Read your Consumer Confidence Report. It lists detected contaminants and any violations from the past year.
4. If byproducts or arsenic concern you, look for a filter certified for that contaminant by NSF, IAPMO, WQA, CSA or UL, and confirm the exact model in the certifier’s online listing.

Note: utilities may have resolved issues since October 7, 2026. Check each utility’s EPA ECHO report or its latest Consumer Confidence Report for current status.

Sources

• TCEQ: State of Texas Public Drinking Water Program 2024 Annual Compliance Report
• TCEQ: Public Water System Supervision Program
• USGS: Arsenic and radionuclide occurrence in groundwater of the Gulf Coast Aquifer System in Houston, Texas, 2007–11
• Texas Water Development Board: Ogallala Aquifer
• EPA: National Primary Drinking Water Regulations
• EPA ECHO: Detailed Facility Reports (linked from each utility page)
• TapWaterSafety.org methodology