Buying Land in McMullen County, Texas

A dedicated groundwater district for a very small county

McMullen County is covered by its own groundwater conservation district -- the McMullen Groundwater Conservation District -- rather than relying on a neighboring district's boundary or going without one entirely. The district's creation followed the standard two-step process for Texas GCDs: the Legislature authorized it, and McMullen County voters then confirmed it directly at the ballot box in November 2001. For a county this sparsely populated, having a dedicated local groundwater authority (rather than being folded into a larger multi-county district, or left uncovered) is itself a notable, checkable fact, and it means well permitting, spacing rules, and any production limits are set by a board answerable specifically to McMullen County landowners rather than a district spanning several counties with different priorities.

That said, the specifics of the district's current rules -- exempt-well thresholds, non-exempt permit requirements, and any spacing or production caps -- are the kind of detail that changes over time and should be confirmed directly with the district office rather than assumed from its founding history alone.

Ranching country with a real oil-and-gas layer

Most of McMullen County's roughly 1,159 square miles has historically been given over to farming and ranching, and that remains the land's dominant character. But the county is also a genuine, active oil-and-gas producer: a July 2025 industry snapshot ranked McMullen #19 among all Texas counties for oil and gas production by barrels of oil equivalent -- a meaningful ranking for a county with well under a thousand year-round residents. For a buyer, that combination means it's worth checking a specific tract's mineral-ownership history and whether any lease, well, or pipeline easement already runs across it, even where the surface use still reads as straightforward ranch or farm land. A title search and a conversation with the seller about any existing surface-use agreements are worth doing before closing, not after.

Septic permitting: no confirmed local authorized-agent status

This research turned up no evidence that McMullen County has taken on TCEQ OSSF authorized-agent status, the delegation that lets a county run its own septic permitting program day to day. McMullen County falls under TCEQ Region 16, based in Laredo, so absent a confirmed local program, plan on that regional office being the point of contact for a septic (on-site sewage facility) permit application on unincorporated county land. Given the county's small size and limited staff, it would not be surprising if this remains the case going forward, but authorized-agent status can change, so confirm current status, required site/soil evaluation steps, and fees directly with either the county or TCEQ Region 16 before budgeting a system.