Buying Land in Medina County, Texas

Water: the Edwards Aquifer changes everything here

The single fact that shapes more of Medina County's land-use rules than anything else is geological: the county sits over the Edwards Aquifer, the primary drinking-water source for San Antonio and much of South Central Texas. That drives a genuinely doubled groundwater-permitting structure -- the region-wide Edwards Aquifer Authority plus the county's own separate Medina County Groundwater Conservation District, with EAA's own materials specifically confirming that a well drawing from the Edwards Aquifer here must register with the county GCD in addition to the EAA process. It also means the county falls inside the aquifer's mapped Contributing Zone, the watershed that drains toward the aquifer's recharge area, which is why enhanced septic-system rules described below apply here in a way they don't in most of rural Texas. See the standalone well-water page for the mechanics of the dual EAA/county-district system -- exempt-well thresholds, registration and permit fees, and what the Edwards Aquifer's aquifer-wide pumping caps mean for a new non-exempt water right.

Septic permitting: enhanced rules tied to the Contributing Zone

Because Medina County falls within the Edwards Aquifer's Contributing Zone under 30 TAC Chapter 213, on-site sewage facility (septic) permitting here isn't governed by the state's baseline 30 TAC Chapter 285 rules alone. TCEQ imposes enhanced standards on new OSSF installations within the Contributing and Recharge Zones -- tighter setbacks from features that drain toward the aquifer, additional casing and construction requirements for any nearby well, and a strong push toward aerobic treatment with spray or drip distribution rather than a conventional subsurface absorption field. In practical terms, that commonly means 2 to 4 additional weeks of review time and an extra few hundred dollars in Edwards Aquifer-specific fees layered on top of a standard septic permit, plus added notification requirements if an existing system in the zone ever needs repair.

This research found septic applications for Medina County routed to the TCEQ Region 13 office in San Antonio, without confirming that the county itself holds a formal TCEQ OSSF authorized-agent delegation; Medina County does require a professional soil evaluation before any septic permit is issued, consistent with a site this close to sensitive recharge geography. Confirm current authorized-agent status, required Edwards Aquifer plan review, and fee schedules directly with TCEQ Region 13 or the county before budgeting a system -- and if the parcel is anywhere near a stream, draw, or other feature that could drain toward the aquifer, ask specifically whether it falls in the Contributing Zone, the Recharge Zone, or neither, since the applicable rules genuinely differ.