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Water wells in the Middle Trinity, Kerr County, Texas

Home water wells that draw from the Middle Trinity in Kerr County, Texas are typically 500 to 690 feet deep (median 600 ft, 520 wells drilled in the last 10 years). It is the county's main layer: 58% of the 900 wells the state's model covers. They run about 60 feet deeper than the county's median well (540 ft). Estimated cost of a complete well at the median depth: $17,500 to $42,500.

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 Kerr CountyMiddle Trinity across Texas

Which layer Kerr County wells draw from

Under Kerrville, Kerr County

County home wells covered by the Hill Country Trinity model (in the last 10 years).

Home wells in Kerr 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: Kerr County

Key figures

Typical depth (middle half)
500 to 690 feet
Median depth
600 feet
Deepest 10% are past
750 feet
Water level (median)
405 feet
468 wells
Yield (median)
20 gpm
400 wells, gallons per minute
Wells used
520
In the last 10 years
Share of the county's wells
58%
All years on file
1,143
median 580 ft, since 1999
Confidence
Standard (30 or more wells)

When the wells were finished, the water stood a median 405 feet below the surface (468 wells).

Which layer Kerr County wells draw from

County home wells covered by the Hill Country Trinity model (in the last 10 years).

What this layer is

The Middle Trinity groups the lower member of the Glen Rose Limestone, the Hensell Sand and the Cow Creek Limestone. It is the layer most Hill Country home wells are completed in. Under it, the Hammett Shale separates it from the Lower Trinity.

Checked against the state's own aquifer codes: where our method names this layer, the state agrees in 85% of 1,503 wells.

More about the Middle Trinity

Depth over time

New home wells in this layer in Kerr County are deeper than 20 years ago: the median went from 540 feet (2003 to 2007) to 610 feet (2021 to 2025), 13% 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
2001–2005540174
2006–2010540256
2011–2015560159
2016–2020600204
2021–2025610325
202661024

Places in Kerr County with wells in this layer

Common questions

How deep is a well in the Middle Trinity in Kerr County?

Home water wells that draw from the Middle Trinity in Kerr County, Texas are typically 500 to 690 feet deep (median 600 ft, 520 wells drilled in the last 10 years).

How many Kerr County wells draw from this layer?

It is the county's main layer: 58% of the 900 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 405 feet below the surface (468 wells).

What a well costs here

At the median depth for this layer in Kerr County (600 feet), a complete home well would cost roughly $17,500 to $42,500: $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 (500 to 690 feet) the range runs from $15,000 to $48,000. 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.

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 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/kerr-county/middle-trinity. License CC BY 4.0. https://doi.org/10.5281/zenodo.24126380.

Sources