United States Last reviewed: September 29, 2026

Texas Tap Water Quality

Q: Is tap water safe to drink in Texas?

Yes in the major cities: Houston, Dallas, San Antonio, Austin, and Fort Worth all meet EPA standards. Small rural systems carry most of the state's violations, and boil notices after freezes or breaks should always be followed.

Q: Why does Texas issue so many boil-water notices?

Any pressure loss triggers a precautionary notice, and with 4,600+ systems, aging rural infrastructure, hurricanes, and freeze events, Texas simply has more trigger events than anywhere else.

Q: What is special about San Antonio's water?

It flows from the Edwards Aquifer, a karst limestone system so clean the city historically needed only disinfection: now supplemented by desalination and storage projects to reduce drought dependence on the aquifer.

about 4,600

Community water systems

City reports on this site

Tracked contaminants

September 29, 2026

Data reviewed

Check a Texas ZIP Code

Overview

Texas runs the nation's largest water-system roster, roughly 4,600 community systems, from Dallas, Houston, and San Antonio's fully compliant metro giants (San Antonio's Edwards Aquifer supply needs little more than disinfection) down to thousands of small rural utilities where most problems live.

The 2021 winter storm exposed the grid-water nexus (nearly 15 million Texans under boil notices at the peak), and the state leads the country in boil-water advisories most years. Naturally occurring arsenic and radium in West Texas and Hill Country groundwater, nitrate in the Panhandle, and colonias along the border still lacking full service round out a state of extremes.

Common Contaminants in Texas

Radium and radionuclides

Hill Country and West Texas granite-belt groundwater produces the nation's largest cluster of small-system radium violations

Arsenic

Naturally elevated across West Texas basins; dozens of small systems run treatment or variances

Nitrate

Panhandle and agricultural-belt groundwater exceedances in small systems and private wells

Boil-water advisories

Pressure-loss advisories after storms, freezes, and main breaks are the state's most common consumer-facing event

Violations & Compliance

Metro systems are reliably compliant; Texas' violation totals lead the nation mostly because its small-system count does. Radionuclides and arsenic dominate health-based exceedances, and hardening systems against freeze events is the post-2021 priority.

Water Hardness in Texas

Very hard, typically 150–350 mg/L. From Edwards Aquifer limestone water in San Antonio to Dallas-Fort Worth's reservoir blends, most Texas systems are hard to very hard; El Paso and Houston vary by source.

Soft

Moderate

Hard

Very Hard

Hardness by city in Texas