Planning a well in Grayson County?

Welcome to Grayson County, Texas — DFW Well Service provides water well drilling and pump repair across Grayson County

Water Well Drilling & Service in Grayson County, Texas

Grayson County sits over the Woodbine aquifer system (outcrop in a NE-SW band through central and eastern Grayson County; dips eastward into Fannin/Lamar/Red River counties). Most residential wells target the Woodbine Formation / Woodbine Aquifer; depth varies meaningfully across the county and is best estimated from neighboring TWDB well records. Drilling is regulated by the Red River GCD, which requires a pre-drilling permit. Local water quality consideration: Iron and manganese in the Woodbine are documented problems and treatment is commonly required; the lower Woodbine zones yield the most water, while the upper zone yields little and runs very high in iron.

What’s Under Grayson County: a Layer-by-Layer Look

About this diagram

This cross-section shows the actual rock formations beneath Grayson County, from topsoil down to the Woodbine aquifer system.

Tap any layer in the image, or any layer in the list, to explore each layer and what it means for drilling a well on your property.

Isometric geological cross-section cube illustration showing Grayson County, Texas stratigraphy — Topsoil, Upper Cretaceous units above Woodbine (Pawpaw Fm, Eagle Ford Shale, Austin Chalk), Woodbine Formation / Woodbine Aquifer, Fredericksburg/Washita interval, and the Woodbine aquifer at the base.
Hover or tap a layer in the cube to see formation details.

Grayson County stratigraphy — top to bottom

Topsoil — Blackland to Post Oak transition

0–15 ft

Reddish-brown sandy clay loam.
Austin Chalk margin

15–60 ft

Upper Cretaceous cover above the Woodbine (Pawpaw Formation, Eagle Ford Shale, Austin Chalk); yields only small amounts locally and is not a dependable residential aquifer.
Woodbine Formation

60–250 ft

Sandstone interbedded with shale and clay — three water-bearing zones, the lower two typically developed. Outcrops in a NE–SW band through central and eastern Grayson County; the green-gray glauconitic tint is its visual signature.
Primary aquifer target
Trinity (Antlers Formation)

250–350 ft

The deeper alternative. It surfaces mainly in western and northwestern Grayson County and dips beneath younger rock to the southeast. It is the Paluxy and Twin Mountains merged into one body (the Antlers), because the Glen Rose Limestone is missing across Grayson County (TWDB Report 269). Thickness runs ~400 ft near the surface to ~900 ft to the southeast — one county well logged 870 ft of Antlers.
Aquifer

Grayson County Quick Facts

Primary Aquifer
Woodbine

Secondary: Trinity (Antlers)

Typical Well Depth
Varies by location

We estimate from nearby well records

Groundwater District
Red River GCD
Confinement
outcrop in a NE-SW band through central and eastern Grayson County; dips eastward into Fannin/Lamar/Red River counties

Water Quality Notes

  • Iron and manganese in the Woodbine are documented problems and treatment is commonly required; the lower Woodbine zones yield the most water, while the upper zone yields little and runs very high in iron
  • Woodbine water is generally fresh down to about 1,500 ft of well depth, turning slightly to moderately salty below that

Cities We Serve in Grayson County

What's Under Grayson County: the Geology Story

Drilling in Grayson County means starting in topsoil, working through Quaternary alluvium (Red River), Upper Cretaceous units above Woodbine (Pawpaw Fm, Eagle Ford Shale, Austin Chalk), to reach the Woodbine Formation / Woodbine Aquifer — the producing zone for most domestic wells.

The full layer-by-layer stratigraphy is laid out under the cube above. Well depth in Grayson County varies by property location and overburden thickness; your driller can review TWDB records for neighboring wells to refine the expected completion zone before drilling.

Permits & Regulations in Grayson County

Grayson County wells are regulated by the Red River GCD. A pre-drilling permit is required before any new well is constructed. DFW Well Service submits the permit application as part of our drilling process.

Full Grayson County permit & regulations →

Frequently Asked Questions about Grayson County Wells

What aquifer is under Grayson County?
Grayson County wells primarily produce from the Woodbine aquifer system (outcrop in a NE-SW band through central and eastern Grayson County; dips eastward into Fannin/Lamar/Red River counties). Trinity (Antlers) is a secondary target in parts of the county.
How deep are wells typically drilled in Grayson County?
Residential well depth in Grayson County varies meaningfully with property location and the producing formation, so there's no single countywide figure we can responsibly quote. Your driller can review TWDB well records for neighboring properties to estimate the expected depth before drilling, and the per-formation geology of the county is laid out on this page.
What water quality issues are common in Grayson County wells?
Iron and manganese in the Woodbine are documented problems and treatment is commonly required; the lower Woodbine zones yield the most water, while the upper zone yields little and runs very high in iron. Woodbine water is generally fresh down to about 1,500 ft of well depth, turning slightly to moderately salty below that. Water testing after drilling — and periodically thereafter — is recommended for every private well in the county.
Does Grayson County require a permit to drill a water well?
Yes. You need a permit before drilling. The Red River GCD — the local district that permits wells — covers Fannin and Grayson counties. See the Grayson County permit and regulations page for the full process.
What's the main producing formation in Grayson County?
The primary producing formation is the Woodbine Formation / Woodbine Aquifer — The county's main water source. It reaches the surface (the outcrop) in a northeast-southwest band through central and eastern Grayson County and dips deeper to the east. Up to ~600 ft thick underground, with about 160 ft of freshwater on average; wells usually tap the lower two of its three water-bearing zones. Its green-gray tint comes from glauconite, a greenish mineral that can color the water. Most Grayson County residential wells are completed in this interval.

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