Texas county well guide

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

About 8,285 households in Denton County, 3% of the county, rely on a private well. Nobody tests that water unless the owner does.

Labs within 40 milesLicensed contractors
3%of households on a private well
Share on wells, county vs state
Denton County3%
Texas average5%
60licensed contractors serve the county
19 mito the nearest certified lab, SPL, Inc. – Plano
Nostatewide test required when a home is sold

Most of Denton County is on public water, but an estimated 8,285 households still rely on a private well. This page covers the rules, labs and licensed contractors that serve them.

Local rules for wells in Denton County

Private wells in Denton County follow Texas's statewide rules, administered by Texas Department of Licensing and Regulation. No water test is required by the state when a new well is completed. There is no statewide test requirement when a home is sold, though lenders often ask for one. The cards below show the details and the official sources.

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 Denton County

4 certified labs within 40 miles serve Denton County, starting with SPL, Inc. – Plano in Plano (about 19 miles from the county center). Each card below shows whether the lab takes homeowner samples and which tests it is certified for.

4 certified labs within 40 miles

Licensed well contractors serving Denton County

60 licensed contractors serve Denton County, including A & V Water and A-5 Services LLC. Each profile carries the state license number and the date we checked it, and the filters below sort them by drilling, pump work or treatment.

Well depth and water chemistry

Wells in Denton County typically reach 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. What comes up with the water depends on the aquifer, and across Texas the usual suspects are nitrate (high plains, rolling plains, central texas farm country), arsenic (southern high plains. A first full panel tells you which of them apply to your well.

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: Collin County, Dallas County, Tarrant County, Wise County.

What well work costs in Denton 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 Denton County well owners ask

How many homes in Denton County are on a well?

About 8,285, or 3% 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 Denton County?

SPL, Inc. – Plano in Plano, about 19 miles away. Call first to ask whether they accept homeowner samples.

Do I need a permit to drill a well in Denton 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 Denton 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.