Texas Water Quality Guide
Understanding water quality across the Lone Star State, from the humid Gulf Coast to the arid West Texas plains, and everything in between.
Environmental Health Research
Expert Reviewed
This content has been reviewed by Dr. Sarah Chen, PhD, Environmental Science Advisor, to ensure accuracy and alignment with current environmental science standards.
Last reviewed: April 2026
Texas Water System Overview
Texas has the second-largest population and second-largest land area in the nation, creating immense diversity in water sources and quality. The state relies on a mix of surface water from lakes and rivers, groundwater from nine major aquifers, and increasingly, alternative sources like desalination and recycled water.
Major Water Sources
- Surface Water: About 60% of Texas water supply comes from reservoirs and rivers, including Lake Texoma, Lake Travis, and the Rio Grande
- Ogallala Aquifer: The massive High Plains aquifer supplies irrigation and municipal water to the Panhandle and West Texas
- Edwards Aquifer: One of the most productive aquifers in the world, serving San Antonio and Central Texas
- Gulf Coast Aquifer: Supplies Houston and coastal communities
- Carrizo-Wilcox Aquifer: Important source for East and Central Texas
Climate and Water Challenges
Texas spans multiple climate zones, from humid subtropical in the east to semi-arid in the west. Annual rainfall varies from over 50 inches along the Louisiana border to less than 10 inches in El Paso. This diversity creates vastly different water quality challenges across the state, with drought, flooding, and extreme weather events all affecting water systems.
Regional Water Quality Variations
Texas water quality varies dramatically by region due to differences in geology, climate, land use, and population density. Understanding your region's specific challenges helps you make informed decisions about water treatment and filtration.
East Texas
The piney woods of East Texas receive abundant rainfall and have numerous surface water reservoirs. Water tends to be softer than other Texas regions. However, iron and manganese from underlying geology can cause staining and taste issues. Some areas have elevated levels of naturally occurring radionuclides.
Gulf Coast (Houston Area)
Houston Area Considerations:
- Surface water from Lake Houston and Lake Livingston
- Groundwater from the Gulf Coast Aquifer facing subsidence issues
- Hurricane and flood events can temporarily affect water quality
- Industrial contamination in some areas near petrochemical facilities
- Disinfection byproducts can be elevated due to organic matter in source water
Central Texas (Austin/San Antonio Corridor)
The Texas Hill Country sits atop the Edwards Aquifer, one of the world's most remarkable groundwater systems. Water from the Edwards is naturally high quality, filtered through hundreds of feet of limestone. However, the karst geology makes the aquifer vulnerable to contamination from the surface. San Antonio and Austin both draw from this system, supplemented by surface water from Highland Lakes and other sources.
North Texas (Dallas/Fort Worth Metroplex)
The DFW area relies primarily on surface water from numerous reservoirs including Lake Ray Hubbard, Lake Lavon, Lewisville Lake, and Lake Texoma. Hard water is typical, with high mineral content affecting taste and causing scale buildup. The region has invested heavily in water treatment to meet growing demand.
West Texas and the Panhandle
The Ogallala Aquifer sustains communities across the High Plains, but water levels are declining due to agricultural pumping. Groundwater in this region often has elevated levels of fluoride, arsenic, and total dissolved solids. Some communities face water quality challenges that require advanced treatment or alternative supplies.
Rio Grande Valley
The border region faces unique challenges including aging infrastructure, rapid population growth, and water scarcity. The Rio Grande itself has high salinity and requires extensive treatment. Some colonias (unincorporated communities) still lack adequate water and wastewater infrastructure.
Common Contaminants in Texas
Texas water systems face various contaminant challenges depending on geography, land use, and water source. Here are the most common concerns across the state.
Arsenic
Natural arsenic in groundwater is a significant concern in parts of West Texas, the Panhandle, and South Texas. Some small water systems have struggled to meet the EPA's 10 ppb standard, requiring treatment upgrades or alternative water sources.
Fluoride
Parts of West Texas have naturally occurring fluoride levels that exceed the EPA's secondary standard of 2.0 mg/L and sometimes the primary standard of 4.0 mg/L. While added fluoride benefits dental health, excessive natural fluoride can cause dental and skeletal fluorosis.
Nitrates
Agricultural and Septic System Impact:
Nitrate contamination affects many Texas water supplies, particularly in agricultural areas and regions with high densities of septic systems. The Texas Panhandle, Central Texas, and parts of South Texas have documented nitrate issues. Infants under six months are most vulnerable to nitrate exposure.
Radium and Radioactivity
Some Texas groundwater sources contain elevated levels of naturally occurring radium-226 and radium-228, particularly in parts of the Gulf Coast, East Texas, and Central Texas. Combined radium above 5 pCi/L requires treatment or blending with cleaner water sources.
Atrazine and Agricultural Chemicals
The herbicide atrazine and other agricultural chemicals have been detected in surface water sources that drain agricultural land. While typically below EPA limits, these contaminants are concerning to many residents seeking to minimize pesticide exposure.
PFAS
PFAS contamination has been identified near military bases and industrial sites across Texas. Areas near former and active Air Force bases, including those in San Antonio, Fort Worth, and El Paso, have documented PFAS in groundwater.
Rural vs. Urban Water Quality
Water quality experiences differ significantly between urban and rural Texas, with each facing distinct challenges and advantages.
Urban Systems
Major Texas cities operate sophisticated water treatment plants with multiple barriers for contaminant removal. Houston, Dallas, San Antonio, and Austin invest heavily in infrastructure and monitoring. However, urban systems face challenges from aging distribution pipes, disinfection byproduct formation, and occasional water main breaks.
Small Community Water Systems
Small System Challenges:
- Limited budgets for treatment upgrades
- Fewer staff and technical resources
- Higher per-capita costs for compliance
- Aging infrastructure in need of replacement
- More vulnerable to single-source contamination
Private Wells
Approximately 2.5 million Texans rely on private wells that are not regulated by the state or EPA. Well owners are responsible for their own water quality testing and treatment. Common issues include bacteria, nitrates, and naturally occurring contaminants. The Texas Commission on Environmental Quality provides guidance but does not regulate private wells.
Colonias
Some unincorporated communities along the Texas-Mexico border still lack adequate water infrastructure. State and federal programs are working to extend safe water services to these areas, but challenges remain. Residents in colonias should contact their county or the Texas Water Development Board for assistance.
Resources for Texas Residents
State and Federal Resources:
Testing Your Water
Texas public water systems must provide annual Consumer Confidence Reports (CCRs) to customers. These reports detail contaminant levels and any violations. Private well owners should test annually for bacteria and nitrates, and periodically for other contaminants based on local conditions. TCEQ maintains a list of accredited laboratories.
Filtration Recommendations
Based on common Texas water quality issues, consider these filtration options:
- For hard water: Water softeners or salt-free conditioners
- For arsenic: Reverse osmosis or adsorptive media filters (NSF 53 certified)
- For nitrates: Reverse osmosis or ion exchange (NSF 58 certified)
- For radium: Water softeners, reverse osmosis, or ion exchange
- For taste/odor: Activated carbon filters (NSF 42 certified)
- For comprehensive protection: Whole-house or point-of-use reverse osmosis
Boil Water Notices:
Texas utilities issue boil water notices when water pressure drops or contamination is suspected. During a notice, bring water to a rolling boil for at least one minute before drinking, cooking, or brushing teeth. Follow your utility's guidance on when the notice is lifted.