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Water wells in the lower Trinity (Twin Mountains and Travis Peak), Hill County, Texas

Only 17 home water wells that draw from the lower Trinity (Twin Mountains and Travis Peak) in Hill County, Texas have been reported since 2001, so treat this as a rough guide: the middle half are 970 to 1,200 feet deep (median 1,060 ft). It is a minor layer here: just 1% of the 357 wells the state's model covers; the main one is the Woodbine Aquifer (48%). They run about 700 feet deeper than the county's median well (360 ft). Estimated cost of a complete well at the median depth: $29,000 to $70,000.

This page is based on fewer than 30 wells, so it is kept out of search engines until more reports come in. Treat every figure as a rough guide.

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

All wells in Hill CountyLower Trinity (Twin Mountains and Travis Peak) across Texas

Which layer Hill County wells draw from

County home wells covered by the Northern Trinity and Woodbine model (in the last 10 years).

Home wells in Hill County

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+

Dark line: Hill County

Key figures

Typical depth (middle half)
970 to 1,200 feet
Median depth
1,060 feet
Deepest 10% are past
1,297 feet
Water level (median)
620 feet
17 wells
Yield (median)
15 gpm
17 wells, gallons per minute
Wells used
17
Since 2001
Share of the county's wells
1%
All years on file
17
median 1,060 ft, since 2005
Confidence
Few wells (10 to 29)

When the wells were finished, the water stood a median 620 feet below the surface (17 wells).

What this layer is

This group is the lower half of the Trinity in North and Central Texas, the Twin Mountains Formation in the north and the Travis Peak to the south: the Hensell sand, the Pearsall shale and limestone, and the Hosston sandstone and conglomerate at the bottom. The state's model draws three layers, each at least 30 feet thick. This atlas reports them together because the method cannot place a well in one of the three reliably. North and west of Fort Worth they are the lower part of the undivided Antlers Formation.

More about the lower Trinity (Twin Mountains and Travis Peak)

Depth over time

Too few wells per period in this layer in Hill County to compare depth over time. Since 2005, 17 home wells have been reported, with a median of 1,060 feet.

PeriodMedian depth (ft)Wells
2001–2005under 10 wells1
2006–2010under 10 wells5
2011–2015under 10 wells4
2016–2020under 10 wells3
2021–2025under 10 wells4

Common questions

How deep is a well in the lower Trinity (Twin Mountains and Travis Peak) in Hill County?

Only 17 home water wells that draw from the lower Trinity (Twin Mountains and Travis Peak) in Hill County, Texas have been reported since 2001, so treat this as a rough guide: the middle half are 970 to 1,200 feet deep (median 1,060 ft).

How many Hill County wells draw from this layer?

It is a minor layer here: just 1% of the 357 wells the state's model covers; the main one is the Woodbine Aquifer (48%). Only 47% 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 deep does the water stand?

When the wells were finished, the water stood a median 620 feet below the surface (17 wells).

What a well costs here

At the median depth for this layer in Hill County (1,060 feet), a complete home well would cost roughly $29,000 to $70,000: $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 (970 to 1,200 feet) the range runs from $27,000 to $78,500. 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.

How these numbers are made

We count new and replacement domestic (home) wells with a valid depth on their report. 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 47% 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/hill-county/twin-mountains. License CC BY 4.0. https://doi.org/10.5281/zenodo.24126380.

Sources