State Well Water Guide
Texas Private Well Water Guide
Texas has approximately 1.5 million private water wells, with rural and suburban residents across the Hill Country, West Texas, and the Panhandle commonly relying on groundwater. The state's primary well water concerns include naturally occurring arsenic (particularly in West Texas and the Hill Country), high nitrates from agricultural and septic sources, radium and uranium in granite-dominated regions, and bacterial contamination in shallow alluvial wells. The Texas Commission on Environmental Quality (TCEQ) oversees public water systems; private wells are the landowner's responsibility.
Testing Guidance
TCEQ and Texas A&M AgriLife Extension recommend testing private wells annually for bacteria and nitrates as a minimum. Additional testing should be conducted for arsenic (West Texas and Hill Country), radium (Llano Uplift and granitic bedrock areas), fluoride (Trans-Pecos and parts of West Texas), iron and manganese (East Texas), hydrogen sulfide (Permian Basin and some Gulf Coast areas), and PFAS near military installations or industrial areas. New wells should receive a comprehensive baseline test before first use.
What to Test For in Texas
Total coliform bacteria and E. coli — annual minimum for all wells
Nitrates — annual for wells near agriculture or septic systems
Arsenic — West Texas, Hill Country (Edwards Plateau), and Trans-Pecos wells
Radium-226 and Radium-228 — Llano Uplift (Llano, Mason, Gillespie counties) and granite rock regions
Uranium — Hill Country and West Texas granitic geology
Fluoride — Trans-Pecos region and parts of West Texas (naturally elevated)
Iron and manganese — East Texas Pineywoods and Post Oak Savanna regions
Hydrogen sulfide — Permian Basin and Gulf Coast areas
PFAS — near military installations (Fort Hood, Dyess, Sheppard, Lackland, and others)
Total dissolved solids (TDS) — West Texas; some areas exceed 1,000 mg/L
Common Contamination Risks in Texas
Arsenic from natural geological sources — Permian Basin brines and West Texas groundwater rank among the highest arsenic concentrations in the nation
Radium from Llano Uplift granite — radioactive radium isotopes in groundwater from weathered Precambrian granite across the Texas Hill Country
Nitrate contamination — intensive agriculture in the Panhandle High Plains (Ogallala aquifer region) creates elevated nitrate risk; also common near feedlots
Fluoride — naturally elevated fluoride in many West Texas aquifers, including parts of the Edwards-Trinity and Cenozoic Pecos alluvium
Hydrogen sulfide ('rotten egg' odor) — common in Permian Basin groundwater and some Gulf Coast shallow wells
Saltwater intrusion near the Gulf Coast — aquifer depletion in the Houston-Galveston area has historically caused saltwater encroachment
PFAS contamination — multiple military installations across Texas used AFFF firefighting foam with documented groundwater impacts
Contaminant Guides Relevant to TX Wells
PFAS
Synthetic Chemicals
EPA limit: 4 ppt
Lead
Heavy Metals
EPA limit: 15 ppb (action level)
Nitrates
Agricultural Chemicals
EPA limit: 10 mg/L
DBPs
Disinfection Byproducts
EPA limit: 80 µg/L (TTHMs) / 60 µg/L (HAA5)
Arsenic
Heavy Metals
EPA limit: 10 ppb
Hard Water
Minerals
EPA limit: No federal limit
Chlorine
Disinfection Chemicals
EPA limit: 4 mg/L (MRDL)
Microplastics
Emerging Contaminants
EPA limit: No federal limit
Bacteria
Microbial Contamination
EPA limit: Zero E. coli / < 1 coliform per 100 mL
Fluoride
Minerals
EPA limit: 4 mg/L (MCL) / 2 mg/L (Secondary MCL)
Chromium-6
Heavy Metals
EPA limit: 100 ppb (total chromium)
Copper
Heavy Metals
EPA limit: 1.3 mg/L (action level)
Radon
Radioactive Contaminants
EPA limit: No finalized MCL
Iron & Manganese
Minerals
EPA limit: 0.3 mg/L iron / 0.05 mg/L manganese (aesthetic SMCLs)
Atrazine
Agricultural Chemicals
EPA limit: 3 ppb (0.003 mg/L)
Uranium
Radioactive Contaminants
EPA limit: 30 µg/L (30 ppb)
Perchlorate
Industrial Chemicals
EPA limit: 0.056 mg/L (56 ppb)
VOCs
Industrial Chemicals
EPA limit: Varies by compound: benzene 5 ppb; TCE 5 ppb; PCE 5 ppb; vinyl chloride 2 ppb
Radium
Radioactive Contaminants
EPA limit: 5 pCi/L (combined Ra-226 + Ra-228)
Crypto & Giardia
Microbial Contamination
EPA limit: Zero (treatment technique standard)
Hydrogen Sulfide
Naturally Occurring Compounds
EPA limit: No MCL; Secondary MCL (aesthetic) of 0.05 mg/L
Selenium
Minerals
EPA limit: 50 ppb (0.05 mg/L)
Cadmium
Heavy Metals
EPA limit: 5 ppb (0.005 mg/L)
Mercury
Heavy Metals
EPA limit: 2 ppb (0.002 mg/L)
Barium
Heavy Metals
EPA limit: 2 mg/L
pH
Water Quality Indicators
EPA limit: 6.5–8.5 (secondary standard)
Find a Certified Lab in Texas
Use the Texas state-certified laboratory program to find accredited labs for private well testing. Always verify current certification before submitting samples.
TX Certified Lab Directory ↗Texas Well Water FAQs
Related Pages
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Quick Reference
State program
TX Certified Labs ↗EPA guidance
EPA Private Wells Program ↗State lab directory
TX Certified Labs ↗Minimum Annual Tests
Plus state-specific contaminants listed above
Other State Guides