Well Water and Groundwater Rules in Comal County, Texas

The Edwards Aquifer Authority: special-law jurisdiction over roughly half the county

The Edwards Aquifer Authority (EAA) governs groundwater in the Edwards Aquifer beneath roughly half of Comal County. EAA's jurisdiction covers eight counties total: all of Bexar, Medina, and Uvalde Counties, plus portions of Atascosa, Caldwell, Comal, Guadalupe, and Hays Counties (CORRECTED 2026-09, superseding an earlier list that omitted Atascosa, wrongly included Kinney County, and understated Bexar, Medina, and Uvalde as merely partial rather than full-coverage counties). Unlike the roughly 100 conventional groundwater conservation districts created under Water Code Chapter 36 that cover most of the rest of the state, the EAA was created by its own special state legislation, and its rules are correspondingly stricter in at least one important way: every well in EAA jurisdiction must be registered, including exempt domestic wells that wouldn't need any registration at all under a typical Chapter 36 district. The EAA has also actively imposed staged pumping curtailments on larger permit holders based on aquifer conditions in recent years, a real operational constraint rather than a theoretical one. Confirm a specific parcel's EAA-jurisdiction status and current registration requirements directly with the EAA before assuming a well there is subject to only the general statewide rule of capture.

Comal Trinity GCD: a separate district for the deeper aquifer, created in 2015

The Trinity Aquifer sits beneath the Edwards Aquifer in this part of Texas, and it's managed by an entirely separate body: the Comal Trinity Groundwater Conservation District, created by House Bill 2407 in the 84th Texas Legislature's 2015 session. This is a genuinely recent district as Texas groundwater law goes -- not a body with decades of settled precedent, but one whose rules and management approach are comparatively new and worth checking directly rather than assuming they mirror an older, more established district. For a domestic well drilled into the Trinity Aquifer, the district exempts a well producing up to 25,000 gallons a day from a full operating permit, but that well still has to be registered with Comal Trinity before drilling begins, and the district charges a registration fee even for an exempt well. A well expected to exceed that domestic threshold, or intended for irrigation, commercial, or other non-domestic use, needs an actual operating permit from the district.

The pass-through permit: when a Trinity well needs an EAA sign-off too

The two districts don't operate in fully separate lanes for every well. Where a well is completed into the Trinity Aquifer (or one of its subdivisions) but the drilling has to physically pass through a portion of the overlying Edwards Aquifer to get there, the driller needs a separate "pass-through" permit from the Edwards Aquifer Authority in addition to whatever registration or permit Comal Trinity GCD requires for the Trinity completion itself. This is easy to miss if you're planning a well based only on which aquifer you intend to draw from -- the geology of what the drill bit passes through on the way down can trigger an additional permit requirement regardless of the target aquifer. Before committing to a well design or drilling contractor on Comal County land, ask both the EAA and Comal Trinity GCD directly whether the planned well's path and target zone require one permit or two.

What to verify before relying on a Comal County well

1. Confirm which agency (or agencies) has jurisdiction over a specific parcel -- EAA, Comal Trinity GCD, or both -- directly with each district rather than assuming based on general county-level description.
2. If drilling into the Trinity Aquifer, confirm with Comal Trinity GCD whether the well's projected use and production qualify for the domestic exemption (up to 25,000 gallons/day) or require a full operating permit, and budget for the registration fee either way.
3. If a well's drilling path will pass through the Edwards Aquifer zone en route to a deeper target, confirm directly with the EAA whether a pass-through permit is required before drilling begins.
4. Ask the EAA about current pumping-curtailment status for the area if the parcel sits within EAA jurisdiction, since curtailment stages have changed with aquifer conditions in recent years.