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How deep are water wells in St. Jo, Texas?

Home water wells in and around St. Jo, Texas are typically 189 to 400 feet deep (median 310 ft, 46 wells reported since 2001). Nearly all (96%) are completed in the Trinity, which the state maps here as one undivided unit, the Antlers Formation; by depth, roughly 37% fall in its upper part and 59% in its lower part, an approximate split. Estimated cost of a complete well at the median depth: $10,500 to $25,000.

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 pointMontague County
What is under St. Jo, TexasUnderground column at the center of St. Jo: median well 310 ft, middle half 189 to 400 ft, water at 160 ft, and the layers of the state's model with their thickness.Upper Trinity: 0 to 202 ftUpper TrinityLower Trinity: 202 to 432 ftLower TrinityBelow the base of the Trinity0100200300400500ftGround level · 1,143 ft above sea levelMedian well: 310 ftWater standing in the well from 160 ftWater level160 ftMiddle half189–400 ftMedian well310 ft

Under St. Jo, Montague County

Layers at the center of St. Jo 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 46 real wells.

Home wells in and around St. Jo

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: St. Jo and about 2 miles around it

Key figures

Typical depth (middle half)
189 to 400 feet
Median depth
310 feet
Deepest 10% are past
420 feet
Water level (median)
160 feet
39 wells
Yield (median)
15 gpm
41 wells, gallons per minute
Wells used
46
Since 2001
Inside the city limits
3
the rest within 2 miles
All years on file
46
median 310 ft, since 2003
Confidence
Standard (30 or more wells)

When the wells were finished, the water stood a median 160 feet below the surface (39 wells).

What is under St. Jo, TexasUnderground column at the center of St. Jo: median well 310 ft, middle half 189 to 400 ft, water at 160 ft, and the layers of the state's model with their thickness.Upper Trinity: 0 to 202 ftUpper TrinityLower Trinity: 202 to 432 ftLower TrinityBelow the base of the Trinity0100200300400500ftGround level · 1,143 ft above sea levelMedian well: 310 ftWater standing in the well from 160 ftWater level160 ftMiddle half189–400 ftMedian well310 ft
Layers at the center of St. Jo 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 46 real wells.

Which formation do wells in St. Jo draw from?

Nearly all (96%) are completed in the Trinity, which the state maps here as one undivided unit, the Antlers Formation; by depth, roughly 37% fall in its upper part and 59% in its lower part, an approximate split.

Layer (state's model)ShareWellsTypical depth (ft)
Lower TrinityTwin Mountains and Travis Peak59%27320–400
Upper TrinityPaluxy and Glen Rose37%17135–200
Near or below the base of the Trinity4%2—

Only 37% 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 St. Jo

From the state's model, at 1,143 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)
Upper Trinitysandstone, limestone and marl0202202
Lower Trinitysandstone with shale and limestone202432230

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 St. Jo are getting deeper. For reference, the median was 310 feet in 2011 to 2015 (10 wells) and 330 feet in 2021 to 2025 (16 wells).

PeriodMedian depth (ft)Wells
2001–2005under 10 wells6
2006–2010under 10 wells6
2011–201531010
2016–2020under 10 wells3
2021–202533016
2026under 10 wells5

What a well costs in St. Jo

At the median depth for St. Jo (310 feet), a complete home well would cost roughly $10,500 to $25,000: $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 (189 to 400 feet) the range runs from $7,000 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.

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 St. Jo, Texas?

Home water wells in and around St. Jo, Texas are typically 189 to 400 feet deep (median 310 ft, 46 wells reported since 2001). One in ten goes past 420 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 St. Jo draw from?

Nearly all (96%) are completed in the Trinity, which the state maps here as one undivided unit, the Antlers Formation; by depth, roughly 37% fall in its upper part and 59% in its lower part, an approximate split. This is an estimate from the state's regional model, not a survey of the lot.

How much does a water well cost in St. Jo?

At the median depth (310 feet), a complete well would cost roughly $10,500 to $25,000, 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 St. Jo?

When the wells were finished, the water stood a median 160 feet below the surface (39 wells). The level moves with drought and from one well to the next.

Do I need a permit to drill a well in St. Jo?

St. Jo is inside the Upper Trinity Groundwater Conservation District. Groundwater conservation districts in Texas can require registering or permitting a new well, keeping set distances from property lines and other wells, and paying fees. Rules differ from district to district: ask the district before drilling.

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 37% 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.
  • 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/places/st-jo-tx. License CC BY 4.0. https://doi.org/10.5281/zenodo.24126380.

Sources