Skip to content
ENES
Marketplace

How deep are water wells in San Antonio, Texas?

Home water wells in and around San Antonio, Texas are typically 392 to 800 feet deep (median 521 ft, 454 wells drilled in the last 10 years). Nearly all draw from the Middle Trinity (86%), according to the state's Hill Country Trinity model (TWDB). The model covers 54% of those wells (243). New wells run about 15% shallower than 20 years ago (median 600 ft in 2003 to 2007, 510 ft in 2021 to 2025). Estimated cost of a complete well at the median depth: $15,500 to $38,000.

Updated every day from Texas Water Development Board driller reports. Last update: November 11, 2026, using the state file of November 10, 2026.

See the wells and layers at an exact pointBexar County
What is under San Antonio, TexasUnderground column at the center of San Antonio: median well 521 ft, middle half 392 to 800 ft, water at 272 ft.No state layer model here yet02004006008001,000ftGround levelMedian well: 521 ftWater standing in the well from 272 ftWater level272 ftMedian well521 ftMiddle half392–800 ft

Under San Antonio, Bexar County

The well and the water are the median of 454 real wells. This atlas does not have a state layer model for this area yet.

Home wells in and around San Antonio

Each dot is a home well from a state driller report, colored by depth. Tap one for its details and official report. Tap an empty spot to see what is under that point.

See underground

Well depth (ft)

  • <100
  • 100
  • 200
  • 300
  • 400
  • 600
  • 800+

Dashed line: San Antonio and about 2 miles around it

Key figures

Typical depth (middle half)
392 to 800 feet
Median depth
521 feet
Deepest 10% are past
910 feet
Water level (median)
272 feet
382 wells
Yield (median)
30 gpm
358 wells, gallons per minute
Wells used
454
In the last 10 years
Inside the city limits
91
the rest within 2 miles
All years on file
1,230
median 580 ft, since 1994
Confidence
Standard (30 or more wells)

When the wells were finished, the water stood a median 272 feet below the surface (382 wells).

What is under San Antonio, TexasUnderground column at the center of San Antonio: median well 521 ft, middle half 392 to 800 ft, water at 272 ft.No state layer model here yet02004006008001,000ftGround levelMedian well: 521 ftWater standing in the well from 272 ftWater level272 ftMedian well521 ftMiddle half392–800 ft
The well and the water are the median of 454 real wells. This atlas does not have a state layer model for this area yet.

Which formation do wells in San Antonio draw from?

Nearly all draw from the Middle Trinity (86%), according to the state's Hill Country Trinity model (TWDB). The model covers 54% of those wells (243).

Only 70% bottom out inside the Middle Trinity: the rest keep going deeper but take their water from that layer.

Layer (state's model)ShareWellsTypical depth (ft)
Middle Trinity86%210622–880
Upper Trinity9%21410–700
Lower Trinity5%12557–972

For 98% of these wells the report says where the water enters (the screen or the open hole), and we use the middle of that interval.

Depth over time

New home wells in and around San Antonio are shallower than 20 years ago: the median went from 600 feet (2003 to 2007) to 510 feet (2021 to 2025), 15% less. That usually happens when new homes go up in a different area or drillers switch layers.

PeriodMedian depth (ft)Wells
2001–2005560216
2006–2010680264
2011–2015600245
2016–2020540198
2021–2025510262
202657037

What a well costs in San Antonio

At the median depth for San Antonio (521 feet), a complete home well would cost roughly $15,500 to $38,000: $25 to $60 per foot for drilling, casing and seal, plus $2,500 to $6,500 for the pump, pressure tank, controls and hookup at the well. Across the whole middle half of depths (392 to 800 feet) the range runs from $12,500 to $54,500. This is TerraFunded's estimate from published Texas prices, not a quote, and it leaves out trenching and the line to the house. Get prices from at least two licensed drillers.

Where it sits

Nearby places

Median depth of home wells in each place.

All Texas cities and towns

Common questions

How deep do you have to drill a well in San Antonio, Texas?

Home water wells in and around San Antonio, Texas are typically 392 to 800 feet deep (median 521 ft, 454 wells drilled in the last 10 years). One in ten goes past 910 feet. The depth a given tract needs depends on where it sits and what layers the driller hits.

What aquifer or formation do wells in San Antonio draw from?

Nearly all draw from the Middle Trinity (86%), according to the state's Hill Country Trinity model (TWDB). The model covers 54% of those wells (243). This is an estimate from the state's regional model, not a survey of the lot.

How much does a water well cost in San Antonio?

At the median depth (521 feet), a complete well would cost roughly $15,500 to $38,000, by TerraFunded's estimate from published Texas driller prices. The real price comes from a licensed driller's quote.

How deep is the water in San Antonio?

When the wells were finished, the water stood a median 272 feet below the surface (382 wells). The level moves with drought and from one well to the next.

Do I need a permit to drill a well in San Antonio?

San Antonio is inside the Edwards Aquifer Authority. Groundwater conservation districts in Texas can require registering or permitting a new well, keeping set distances from property lines and other wells, and paying fees. Rules differ from district to district: ask the district before drilling.

How these numbers are made

We count new and replacement domestic (home) wells whose coordinates fall inside the place boundary or within 2 miles of it. We use the last 10 years when there are at least 30 wells; otherwise all since 2001. The median is the middle well and the middle half runs from the 25th to the 75th percentile.

To tell which layer a well draws from, we take the ground elevation at its location, subtract the depth of the interval where water enters (or the bottom of the hole when the report does not give one) and see which layer of the state's model that point falls in.

For 98% of these wells the report says where the water enters (the screen or the open hole), and we use the middle of that interval.

How well it works: In 2,665 wells in the Texas Hill Country where the State of Texas recorded the aquifer, our estimate of the formation the well draws from names the same layer of the state's model in about 76% of them, and that layer or the one next to it in at least 98%.

  • The layers come from the Texas Water Development Board's Hill Country Trinity model, with 1 mile cells. It is a regional model, not a survey of any lot: between one model point and the next, the real depth of each layer can differ.
  • "Near or below the base of the Trinity" means the well reaches the bottom of the model or passes it, often by tens of feet. Older rock that the model does not include may lie there.
  • We never use the model's water levels. The water level on this page is the one each driller measured when the well was finished.

These are depths of real wells drilled nearby, not a promise about any property. Groundwater can change over short distances and with drought. A licensed water well driller can tell you what to expect on a specific tract.

Read the full methodology · Download the data (CSV, CC BY 4.0)

How to cite

TerraFunded (2026). Texas Well Atlas: Underground. From Texas Water Development Board driller reports and groundwater availability models (data as of November 10, 2026). https://terrafunded.com/wells/places/san-antonio-tx. License CC BY 4.0. https://doi.org/10.5281/zenodo.24126380.

Sources