Texas county well guide

Well Water in Atascosa County, TX: Testing, Contractors and Rules

About 1,047 households in Atascosa County, 5% of the county, rely on a private well. Nobody tests that water unless the owner does.

Labs within 40 milesLicensed contractors
5%of households on a private well
Share on wells, county vs state
Atascosa County5%
Texas average5%
30licensed contractors serve the county
31 mito the nearest certified lab, Alamo Analytical Laboratories, Ltd.
Nostatewide test required when a home is sold

About 1,047 homes in Atascosa County are on a private well. That is 5% of households, enough that every township has well owners and few of them have had the water tested recently.

Local rules for wells in Atascosa County

The rules that apply in Atascosa County are set at the state level in Texas. The state does not require a test on a new well, and nothing is required at sale. Some counties and townships add permits or setbacks of their own, so check locally before drilling. The state's own recommendations are below.

At a glance

Water test for a new wellNot required statewide

No statewide test. The driller must hold a TDLR license, build the well to the 16 TAC Chapter 76 standards (setbacks from septic systems and property lines, cement seal, disinfection) and file a State of Texas Well Report within 60 days. Nobody samples the water unless you do. If your county has a groundwater conservation district, it may require the well to be registered or permitted before drilling; domestic wells on larger tracts are usually exempt from permitting but not from registration.

Water test when a home is soldNot required statewide

No statewide requirement. The seller's disclosure notice only says whether the water comes from a well. FHA, VA and USDA loans normally require a bacteria, nitrate and lead sample from an accredited lab before closing, and a few groundwater districts ask for a well inspection when a tract changes hands.

What the state recommends

Texas A&M AgriLife Extension and TCEQ recommend a coliform bacteria test every year and a nitrate test every year, plus a first-time panel of arsenic, fluoride, total dissolved solids, hardness, iron, manganese, sulfate and pH. Add uranium and gross alpha in the Hill Country and the Panhandle, and PFAS near airfields and military bases. Test again after flooding, repairs or any change in taste, color or smell.

Free or low-cost testingAvailable

The Texas Well Owner Network (Texas A&M AgriLife Extension) runs low-cost screening days around the state, usually $10 to $15 a sample for bacteria, nitrate, arsenic and salinity, with results explained at a follow-up meeting. County and city health department labs listed below sell bacteria tests at cost. The DSHS laboratory in Austin also sells mail-in kits.

Getting your water tested near Atascosa County

The nearest certified lab is Alamo Analytical Laboratories, Ltd. in San Antonio, about 31 miles from the county center. There are 3 more within 40 miles, listed below with what each tests for.

4 certified labs within 40 miles

Licensed well contractors serving Atascosa County

Licensed help in Atascosa County includes Alamo Water Wells and Alamo1 Drilling and 28 others. Every listing was matched to the Texas license list; the "verify" link on each profile opens the state lookup.

Well depth and water chemistry

Well depth and water chemistry in Atascosa County follow the rock underneath it. Typical wells here run 100 to 400 ft in the Ogallala on the High Plains; 200 to 800 ft in the Trinity and Edwards limestones of the Hill Country and North Texas; 100 to 600 ft in the Gulf Coast and Carrizo-Wilcox sands of East and South Texas; shallower along river alluvium feet. Contaminants worth testing for in this part of Texas include nitrate (high plains, rolling plains, central texas farm country), arsenic (southern high plains.

Typical well depth

Varies by location. Check the state well record search for logs of nearby wells.

Contaminants to test for
  • Nitrate (High Plains
  • Rolling Plains
  • Central Texas farm country)
  • Arsenic (southern High Plains
  • Gulf Coast
  • Trans-Pecos)
  • Fluoride (West Texas and the Panhandle)
  • Radium and uranium (Hickory aquifer around the Llano Uplift
  • Parts of the Ogallala)
  • High total dissolved solids and salinity (West and South Texas)
  • Coliform bacteria
  • Hardness (Edwards and Trinity limestones)
  • Iron and manganese and hydrogen sulfide (East Texas)
  • PFAS near military airfields

Neighboring counties: Wilson County, Medina County, Bexar County, Frio County.

What well work costs in Atascosa County

Basic bacteria and nitrate test$25 to $75lab fee, homeowner sample
Full panel lab test$150 to $400metals, VOCs, radiologicals
Well inspection$250 to $550flow, pressure, visual, water test
Submersible pump replacement$1,200 to $4,500parts and labor
Pressure tank replacement$400 to $1,200installed
Whole-house treatment system$800 to $6,000softener, iron filter, UV, RO
New well drilled$5,500 to $25,000about $25 to $65 per foot
Shock chlorination$80 to $300or about $20 as a DIY job

National ranges from published 2025 to 2026 contractor pricing. Local quotes vary with depth, access and materials.

Questions Atascosa County well owners ask

How many homes in Atascosa County are on a well?

About 1,047, or 5% of households, based on Census housing data and state well surveys. The share is highest outside the towns with public water.

Where is the closest certified lab to Atascosa County?

Alamo Analytical Laboratories, Ltd. in San Antonio, about 31 miles away. Call first to ask whether they accept homeowner samples.

Do I need a permit to drill a well in Atascosa County?

No statewide test. The driller must hold a TDLR license, build the well to the 16 TAC Chapter 76 standards (setbacks from septic systems and property lines, cement seal, disinfection) and file a State of Texas Well Report within 60 days. Nobody samples the water unless you do. If your county has a groundwater conservation district, it may require the well to be registered or permitted before drilling; domestic wells on larger tracts are usually exempt from permitting but not from registration.

What does a well test cost near Atascosa County?

A bacteria and nitrate test runs $25 to $75 at most certified labs; a full panel with metals is $150 to $400. Mail-in kits cost about the same as walking in.