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How deep are water wells in Sonterra, Texas?

Home water wells in and around Sonterra, Texas are typically 420 to 540 feet deep (median 480 ft, 77 wells reported since 2001). Nearly all are completed in the Washita and Fredericksburg groups (87%), according to the state's Northern Trinity and Woodbine model (TWDB). Estimated cost of a complete well at the median depth: $14,500 to $35,500.

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 pointWilliamson County
What is under Sonterra, TexasUnderground column at the center of Sonterra: median well 480 ft, middle half 420 to 540 ft, water at 280 ft, and the layers of the state's model with their thickness.Above the Woodbine: 0 to 233 ftAbove the WoodbineWoodbine: 233 to 263 ftWashita and Fredericksburg: 263 to 753 ftWashita and Frederick…Upper Trinity: 753 to 1,438 ftUpper Trinitycontinues to 1,791 ft02004006008001,000ftGround level · 857 ft above sea levelMedian well: 480 ftWater standing in the well from 280 ftWater level280 ftMiddle half420–540 ftMedian well480 ft

Under Sonterra, Williamson County

Layers at the center of Sonterra from TWDB's Northern Trinity and Woodbine model (quarter mile cells, summarized here to about 1.3 miles), at true depth scale. The well and the water are the median of 77 real wells.

Home wells in and around Sonterra

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: Sonterra and about 2 miles around it

Key figures

Typical depth (middle half)
420 to 540 feet
Median depth
480 feet
Deepest 10% are past
870 feet
Water level (median)
280 feet
74 wells
Yield (median)
25 gpm
64 wells, gallons per minute
Wells used
77
Since 2001
Inside the city limits
5
the rest within 2 miles
All years on file
77
median 480 ft, since 2003
Confidence
Standard (30 or more wells)

When the wells were finished, the water stood a median 280 feet below the surface (74 wells).

What is under Sonterra, TexasUnderground column at the center of Sonterra: median well 480 ft, middle half 420 to 540 ft, water at 280 ft, and the layers of the state's model with their thickness.Above the Woodbine: 0 to 233 ftAbove the WoodbineWoodbine: 233 to 263 ftWashita and Fredericksburg: 263 to 753 ftWashita and Frederick…Upper Trinity: 753 to 1,438 ftUpper Trinitycontinues to 1,791 ft02004006008001,000ftGround level · 857 ft above sea levelMedian well: 480 ftWater standing in the well from 280 ftWater level280 ftMiddle half420–540 ftMedian well480 ft
Layers at the center of Sonterra from TWDB's Northern Trinity and Woodbine model (quarter mile cells, summarized here to about 1.3 miles), at true depth scale. The well and the water are the median of 77 real wells.

Which formation do wells in Sonterra draw from?

Nearly all are completed in the Washita and Fredericksburg groups (87%), according to the state's Northern Trinity and Woodbine model (TWDB).

Layer (state's model)ShareWellsTypical depth (ft)
Washita and Fredericksburg87%67420–500
Upper TrinityPaluxy and Glen Rose13%10878–930

Only 14% of these wells have the water-bearing interval on their report (reports before about 2012 rarely do). For the others we use the bottom of the hole, which tends to read one layer deeper than where the water actually comes from.

The layers under the center of Sonterra

From the state's model, at 857 feet above sea level. These are the model's depths at that one point, not those of any particular lot.

Depths in feet below ground.
Layer (state's model)Top (ft)Bottom (ft)Thickness (ft)
Above the Woodbineshale, chalk and marl0233233
Woodbinesandstone with shale23326330
Washita and Fredericksburglimestone, marl and clay263753490
Upper Trinitysandstone, limestone and marl7531,438686
Lower Trinitysandstone with shale and limestone1,4381,791353

Depth over time

There are not enough wells in both 2003 to 2007 and 2021 to 2025 (at least 30 in each) to say with confidence whether wells in and around Sonterra are getting deeper. For reference, the median was 480 feet in 2001 to 2005 (23 wells) and 440 feet in 2016 to 2020 (10 wells).

PeriodMedian depth (ft)Wells
2001–200548023
2006–201050020
2011–201546019
2016–202044010
2021–2025under 10 wells4
2026under 10 wells1

What a well costs in Sonterra

At the median depth for Sonterra (480 feet), a complete home well would cost roughly $14,500 to $35,500: $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 (420 to 540 feet) the range runs from $13,000 to $39,000. 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 Sonterra, Texas?

Home water wells in and around Sonterra, Texas are typically 420 to 540 feet deep (median 480 ft, 77 wells reported since 2001). One in ten goes past 870 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 Sonterra draw from?

Nearly all are completed in the Washita and Fredericksburg groups (87%), according to the state's Northern Trinity and Woodbine model (TWDB). This is an estimate from the state's regional model, not a survey of the lot.

How much does a water well cost in Sonterra?

At the median depth (480 feet), a complete well would cost roughly $14,500 to $35,500, 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 Sonterra?

When the wells were finished, the water stood a median 280 feet below the surface (74 wells). The level moves with drought and from one well to the next.

Do I need a permit to drill a well in Sonterra?

In the state's boundary file (current as of November 2019) no groundwater conservation district covers Sonterra. Districts created or enlarged since then are missing from that file, so confirm with the county or TWDB before drilling. Anywhere in Texas the well must be drilled by a licensed driller, who files the report with the state.

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.

Only 14% of these wells have the water-bearing interval on their report (reports before about 2012 rarely do). For the others we use the bottom of the hole, which tends to read one layer deeper than where the water actually comes from.

How well it works: In 7,977 wells in the area of the state's Northern Trinity and Woodbine model (North and Central Texas) 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 74% of them, and that layer or the one next to it in at least 95%; among the 3,130 of those wells that the state places in a Trinity layer (Paluxy to Hosston) it is about 56%.

  • The layers come from the Texas Water Development Board's Northern Trinity and Woodbine model, with quarter mile cells, summarized here to about 1.3 miles. 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.
  • In this model every layer is at least 30 feet thick, even where the real rock is thinner or missing. Thin layers and the edges of the model are approximate.
  • Inside the Trinity this atlas does not name single model layers: it groups the Paluxy and Glen Rose (upper Trinity) and groups the Hensell, Pearsall and Hosston (lower Trinity, Twin Mountains and Travis Peak), because the check against the state's codes shows the method cannot separate them reliably.
  • "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/sonterra-tx. License CC BY 4.0. https://doi.org/10.5281/zenodo.24126380.

Sources