Well Water in Maverick County, Texas

No conservation district, so the rule of capture governs ordinary wells

This research did not find a Chapter 36 Groundwater Conservation District covering Maverick County. That means, for an ordinary shallow water well on Maverick County land, Texas's default rule of capture applies -- a landowner may generally pump as much groundwater as can be put to beneficial use, without a district permitting requirement, spacing rule, or metering mandate, and without much liability if a neighbor's well is affected. Practically, that also means there's no local district maintaining a public well registry or production-monitoring dataset the way a GCD typically would, so information about typical well depths and yields in a specific part of the county is best gathered directly from a local licensed well driller rather than a district database.

The Maverick Basin: a genuinely new, named deep aquifer

In 2021, the Railroad Commission of Texas's Groundwater Advisory Unit -- a group set up specifically to evaluate groundwater encountered during oil-and-gas operations -- announced the identification of a substantial deep aquifer informally named the "Maverick Basin," located thousands of feet underground in the Glen Rose Formation. The formation has been tentatively mapped across at least 3,000 square miles spanning Maverick County and four neighbors: Zavala, Dimmit, Kinney, and Uvalde Counties, with the Glen Rose layer itself roughly 1,000 feet thick through most of that area. This is not a resource that's been part of the county's water planning for decades -- it's a genuinely recent finding, and the practical infrastructure to use it is still being built out.

What makes the Maverick Basin story unusual is how it's being accessed: rather than drilling entirely new water wells, the Railroad Commission has processed and issued nearly a dozen applications under its P-13 well-conversion process, which allows a well originally drilled for oil-and-gas purposes in the Glen Rose Formation to be legally converted into a water-supply well. Testing during the Groundwater Advisory Unit's research indicated that future wells drawing on this aquifer could sustainably produce thousands of gallons of freshwater per day from a single well, and some wells have shown artesian flow -- water rising and flowing at the surface under its own pressure without pumping, a strong practical indicator of a productive, pressurized aquifer. The find was significant enough that the Railroad Commission supplied Eagle Pass Water Works with a formal letter of support for the utility's application for matching federal grant funding from the U.S. Department of the Interior, aimed at building out new water infrastructure tied to this source.

What this means for a private landowner right now

For a typical rural land buyer planning a household well, the Maverick Basin discovery mostly matters as context rather than an immediate option: the wells converted so far are generally former oil-and-gas wells being repurposed for municipal or utility-scale water supply (notably tied to Eagle Pass Water Works), not a new drill-your-own-well program available to any landowner. Whether -- and under what terms -- a private landowner could access this deep aquifer directly is a genuinely open question this research did not find a clear public answer to, and it's worth asking the Railroad Commission's Groundwater Advisory Unit directly rather than assuming private access mirrors the municipal conversion program. It's also worth watching this space over time: because the Maverick Basin was only identified in 2021 and the P-13 conversion program is still an active, developing effort, a formal state Groundwater Availability Model run or GCD-style regulatory framework specific to this aquifer may emerge in the coming years, which could change how it's managed going forward.

• For a household or agricultural well, plan around the shallower, conventional aquifers a local licensed driller would target -- the Maverick Basin's converted wells are thousands of feet deep and tied to specific former oil-and-gas well infrastructure, not a general-access resource yet.
• If a parcel includes an existing plugged or inactive oil-and-gas well in the Glen Rose Formation depth range, ask the Railroad Commission directly whether that specific wellbore has been evaluated, or could be evaluated, for P-13 conversion potential.
• Watch for any future Groundwater Conservation District formation or TWDB Groundwater Availability Model release specific to the Maverick Basin, since the regulatory framework here is still actively developing rather than settled.