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Upper Trinity (Paluxy and Glen Rose): how deep the wells are

Home water wells that draw from the upper Trinity (Paluxy and Glen Rose) in North and Central Texas are typically 200 to 400 feet deep (median 280 ft, 9,322 wells drilled in the last 10 years). In the state's model it is sandstone, limestone and marl. It carries the most weight in Tarrant County (87% of its wells), Denton County (86% of its wells) and Cooke County (62% of its wells). Estimated cost of a complete well at the median depth: $9,500 to $23,500.

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

Depth of wells in the upper Trinity (Paluxy and Glen Rose), by countyThe dot is the median and the bar the middle half for each county. The table below has the figures.02505007501,000 ftParkerParker: 200–260 ftParker: 220 ft220TarrantTarrant: 280–400 ftTarrant: 350 ft350WiseWise: 180–300 ftWise: 220 ft220DentonDenton: 420–562 ftDenton: 460 ft460JohnsonJohnson: 440–580 ftJohnson: 500 ft500CookeCooke: 420–540 ftCooke: 500 ft500WilliamsonWilliamson: 730–870 ftWilliamson: 810 ft810BosqueBosque: 180–324 ftBosque: 238 ft238ErathErath: 132–159 ftErath: 140 ft140HoodHood: 200–340 ftHood: 280 ft280HillHill: 460–520 ftHill: 500 ft500MontagueMontague: 195–266 ftMontague: 220 ft220

Under Weatherford, Parker County

Dot: median. Bar: middle half (25th to 75th percentile). Counties with the most wells in this layer.

What this layer is

This group is the upper half of the Trinity in North and Central Texas: the Paluxy sand on top and the Glen Rose limestone and marl under it. The state's model draws them as two layers, but our check against the state's own aquifer codes shows the method cannot tell them apart reliably, so this atlas reports them together. North and west of Fort Worth the limestone gives way to sand and both become the upper part of the undivided Antlers Formation.

Units the model puts in this layer: Paluxy Formation; upper part of the Antlers Formation in the north and west; Glen Rose Formation; middle part of the Antlers Formation in the north and west.

Source of the layers: TWDB's Northern Trinity and Woodbine model, with quarter mile cells, summarized here to about 1.3 miles.

Key figures

Typical depth (middle half)
200 to 400 feet
Median depth
280 feet
Deepest 10% are past
539 feet
Water level (median)
170 feet
5,214 wells
Yield (median)
15 gpm
7,261 wells, gallons per minute
Wells used
9,322
In the last 10 years
All years on file
20,068
median 260 ft, since 1998
Confidence
Standard (30 or more wells)

Counties where homes draw from this layer

Only counties with at least 10 wells in the layer. The share is of the county's wells that the model covers.

Depth of wells in the upper Trinity (Paluxy and Glen Rose), by countyThe dot is the median and the bar the middle half for each county. The table below has the figures.02505007501,000 ftParkerParker: 200–260 ftParker: 220 ft220TarrantTarrant: 280–400 ftTarrant: 350 ft350WiseWise: 180–300 ftWise: 220 ft220DentonDenton: 420–562 ftDenton: 460 ft460JohnsonJohnson: 440–580 ftJohnson: 500 ft500CookeCooke: 420–540 ftCooke: 500 ft500WilliamsonWilliamson: 730–870 ftWilliamson: 810 ft810BosqueBosque: 180–324 ftBosque: 238 ft238ErathErath: 132–159 ftErath: 140 ft140HoodHood: 200–340 ftHood: 280 ft280HillHill: 460–520 ftHill: 500 ft500MontagueMontague: 195–266 ftMontague: 220 ft220
Dot: median. Bar: middle half (25th to 75th percentile). Counties with the most wells in this layer.
CountyMedian depth (ft)WellsShare of the county's wells
Parker County2203,79554%
Tarrant County3501,48987%
Wise County2201,26136%
Denton County46076086%
Johnson County50056951%
Cooke County50039362%
Williamson County81018915%
Bosque County23814035%
Erath County1401369%
Hood County28011712%
Hill County50010730%
Montague County2209213%
Bell County7808416%
Grayson County4325515%
Hamilton County135306%
Somervell County2802518%
Coryell County388228%
Travis County445222%
Burnet County505181%
Lampasas County360113%

Places where it is the main layer

Where it sits among the model's layers

From top to bottom, with the median depth of the home wells that draw from each:

Layer (state's model)RockMedian depth (ft)Wells
Above the Woodbineshale, chalk and marl1601,739
Woodbinesandstone with shale2601,037
Washita and Fredericksburglimestone, marl and clay2401,050
Upper Trinity (Paluxy and Glen Rose)sandstone, limestone and marl2809,322
Lower Trinity (Twin Mountains and Travis Peak)sandstone with shale and limestone34012,230

Depth over time

Home well depth in this layer has not changed meaningfully in 20 years: the median was 250 feet in 2003 to 2007 and 260 feet in 2021 to 2025 (a difference under 10% or within the margin of error).

PeriodMedian depth (ft)Wells
2001–20052702,943
2006–20102403,887
2011–20152753,206
2016–20202804,270
2021–20252605,204
2026280553

Common questions

How deep is a well in the upper Trinity (Paluxy and Glen Rose)?

Home water wells that draw from the upper Trinity (Paluxy and Glen Rose) in North and Central Texas are typically 200 to 400 feet deep (median 280 ft, 9,322 wells drilled in the last 10 years).

What is the upper Trinity (Paluxy and Glen Rose)?

This group is the upper half of the Trinity in North and Central Texas: the Paluxy sand on top and the Glen Rose limestone and marl under it. The state's model draws them as two layers, but our check against the state's own aquifer codes shows the method cannot tell them apart reliably, so this atlas reports them together. North and west of Fort Worth the limestone gives way to sand and both become the upper part of the undivided Antlers Formation.

How deep does the water stand in these wells?

When the wells were finished, the water stood a median 170 feet below the surface (5,214 wells).

What a well in this layer costs

At the median depth for this layer (280 feet), a complete home well would cost roughly $9,500 to $23,500: $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 (200 to 400 feet) the range runs from $7,500 to $30,500. 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 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 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/formations/paluxy-glen-rose. License CC BY 4.0. https://doi.org/10.5281/zenodo.24126380.

Sources