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

Home water wells that draw from the lower Trinity (Twin Mountains and Travis Peak) in Hamilton County, Texas are typically 430 to 554 feet deep (median 475 ft, 435 wells drilled in the last 10 years). It is the county's main layer: 86% of the 507 wells the state's model covers. They are about as deep as the county's median well (475 ft). In Hamilton County the state maps the Trinity as one undivided unit, the Antlers Formation, so the split between upper and lower Trinity is approximate. Estimated cost of a complete well at the median depth: $14,500 to $35,000.

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 Hamilton CountyLower Trinity (Twin Mountains and Travis Peak) across Texas

Which layer Hamilton County wells draw from

  • Lower Trinity (Twin Mountains and Travis Peak) 86% · 435 wells
  • Near or below the base of the Trinity 8% · 41 wells
  • Upper Trinity (Paluxy and Glen Rose) 6% · 30 wells
  • Washita and Fredericksburg <1% · 1 wells

Under Hamilton, Hamilton County

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

Home wells in Hamilton 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: Hamilton County

Key figures

Typical depth (middle half)
430 to 554 feet
Median depth
475 feet
Deepest 10% are past
611 feet
Water level (median)
334 feet
325 wells
Yield (median)
30 gpm
350 wells, gallons per minute
Wells used
435
In the last 10 years
Share of the county's wells
86%
All years on file
876
median 460 ft, since 2001
Confidence
Standard (30 or more wells)

When the wells were finished, the water stood a median 334 feet below the surface (325 wells).

Which layer Hamilton County wells draw from

  • Lower Trinity (Twin Mountains and Travis Peak) 86% · 435 wells
  • Near or below the base of the Trinity 8% · 41 wells
  • Upper Trinity (Paluxy and Glen Rose) 6% · 30 wells
  • Washita and Fredericksburg <1% · 1 wells
County home wells covered by the Northern Trinity and Woodbine model (in the last 10 years).

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.

In Hamilton County the state maps the Trinity as one undivided unit, the Antlers Formation, so the split between upper and lower Trinity is approximate.

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

Depth over time

New home wells in this layer in Hamilton County are deeper than 20 years ago: the median went from 430 feet (2003 to 2007) to 475 feet (2021 to 2025), 11% more. Deeper wells do not always mean the water dropped: a driller may be going for another layer, better water or more reserve.

PeriodMedian depth (ft)Wells
2001–2005428168
2006–2010450136
2011–2015458126
2016–2020480163
2021–2025475257
202644426

Places in Hamilton County with wells in this layer

Common questions

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

Home water wells that draw from the lower Trinity (Twin Mountains and Travis Peak) in Hamilton County, Texas are typically 430 to 554 feet deep (median 475 ft, 435 wells drilled in the last 10 years).

How many Hamilton County wells draw from this layer?

It is the county's main layer: 86% of the 507 wells the state's model covers. For 97% 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 deep does the water stand?

When the wells were finished, the water stood a median 334 feet below the surface (325 wells).

What a well costs here

At the median depth for this layer in Hamilton County (475 feet), a complete home well would cost roughly $14,500 to $35,000: $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 (430 to 554 feet) the range runs from $13,500 to $39,500. 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.

For 97% 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 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.
  • In this area, north and west of Fort Worth, the state maps the Trinity as one undivided unit, the Antlers Formation. The model cuts it into layers by depth; the split between upper and lower Trinity shown here is approximate, and the depth ranges are the solid part.
  • "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/hamilton-county/twin-mountains. License CC BY 4.0. https://doi.org/10.5281/zenodo.24126380.

Sources