New TCEQ rules are landing right now that could reshape how aquifer storage and recovery projects get permitted in Central Texas. For environmental consultants working in the Edwards Aquifer region, the implications are worth understanding in detail.
Background
The Texas Legislature passed SB 616 and SB 1061 during the 89th Session in 2025. SB 616 addressed a longstanding regulatory conflict: existing TCEQ rules prohibited all injection wells from transecting the Edwards Aquifer in Williamson County, including aquifer storage and recovery (ASR) wells designed to inject treated surface water into deeper formations below the aquifer for future supply. In one of the fastest-growing regions in the country, that blanket prohibition was blocking an important water supply tool.
The fix was a targeted carve-out. SB 616 maintains the prohibition on waste injection wells while authorizing TCEQ to approve ASR injection wells that transect the Edwards Aquifer in two specific geographies: Williamson County east of I-35, and Medina County. The legislature required TCEQ to adopt implementing rules by March 1, 2026.
Where Things Stand
TCEQ published the proposed rulemaking in November 2025 under Rule Project No. 2025-033-331-WS, amending 30 TAC ยง331.19. The rule is active now and implements SB 616's new exception alongside SB 1061's separate changes to Class III production area authorization (PAA) procedures for in-situ uranium mining. The March 2026 deadline for rule adoption has arrived, meaning the regulatory framework for the first Edwards-transecting ASR permits is in place or very nearly so.
Potential Impacts on Groundwater Resources
The I-35 corridor is often used as a rough proxy for the Edwards recharge zone boundary, but the geology is more nuanced than that line suggests. Significant portions of the Edwards recharge zone extend east of I-35 in Williamson County, meaning the authorized ASR geography is not simply a confined or artesian zone where injection is proposed. Parts of it sit directly over the recharge zone where the aquifer is most hydraulically connected to the surface.
In Medina County, a large portion of the county is underlain by the Edwards recharge zone, making the subsurface sensitivity there substantial across much of the authorized area.
That context matters for how individual ASR permits will need to be evaluated. The Edwards is a karst aquifer, and karst systems do not respect the boundaries we draw on maps. Fractures, faults, and solution conduits can create hydraulic connections between a proposed injection zone and the overlying Edwards in ways that are difficult to predict without site-specific investigation. Questions that will need careful attention as individual ASR permits move forward include:
- Whether the confining layer between the injection zone and the Edwards is sufficient at a given site to prevent upward migration of injected water
- How injected water quality compares to native Edwards water, and what the implications are for mixing
- Long-term monitoring and reporting requirements to detect any unintended connectivity
- How recharge zone designation under TCEQ's Edwards Aquifer Protection Program interacts with the new ASR permitting pathway
None of this means ASR is the wrong approach. Stored water supply is genuinely critical for this region. But the subsurface geology in both authorized areas is complex, and individual permits will require thorough hydrogeologic analysis.
Potential Impacts on Karst Invertebrates
This is the piece that has not received much attention in commentary on this rule, and it warrants serious consideration.
In Williamson County, USFWS endangered karst invertebrate survey zones include both Zone 1 (where listed species are known to occur) and Zone 3B in areas that overlap with the east-of-I-35 geography where ASR can now be authorized. Zone 1 is the most sensitive designation, representing known occurrence areas for listed species such as Williamson County cave spiders and ground beetles. ASR injection wells that require surface construction, drilling, or associated infrastructure in these zones could trigger Section 7 or Section 10 consultation requirements under the Endangered Species Act.
In Medina County, the picture is more complex still. Karst invertebrate zones 1, 2, 3A, and 3B are all mapped in the county. Given how much of Medina County is underlain by the recharge zone, potential ASR project footprints there could intersect with the full range of survey and consultation triggers depending on exact location. The combination of extensive recharge zone coverage and multi-zone karst invertebrate mapping means biological resource characterization will be a meaningful component of project planning in that county.
There is also the matter of the Jollyville Plateau salamander (Eurycea tonkawae). Mapped critical habitat units for this federally threatened species extend east of I-35 in Williamson County, the same general geography where ASR injection wells are now authorized. The Jollyville Plateau salamander is tied to spring-fed systems and shallow karst. Any ASR project whose surface or subsurface footprint intersects those critical habitat units would likely require formal consultation with USFWS and potentially biological surveys prior to construction. If the lower confining unit is breached by ASR waters, what implications could that have on groundwater flow paths and salamander-occupied springs?
Where Consultants Come In, and Where the Uncertainty Lies
The new rules create a permitting pathway that did not exist before, but they do not resolve the downstream regulatory questions. For environmental consultants, the work likely to follow includes:
- Hydrogeologic investigations and Geologic Assessments supporting ASR permit applications under TCEQ's underground injection control program, with attention to recharge zone characterization
- Karst invertebrate surveys to characterize surface and subsurface biological resources in Zone 1 and Zone 3B areas
- USFWS Section 7 informal or formal consultation support where critical habitat for Eurycea species or karst invertebrates is present
- ESA Section 10 and HCP coordination for projects that cannot avoid listed species habitat
- TCEQ Edwards Aquifer Protection Program compliance review where recharge zone is present within the project footprint
Several areas of genuine uncertainty remain as this rule moves into implementation. First, it is not yet clear how TCEQ will structure the individual permit review process for ASR wells under the new rule: whether permits will require site-specific hydrogeologic review as a matter of course, or whether some will proceed by rule without that level of scrutiny. The presence of recharge zone in both authorized geographies makes the case for robust site-specific review stronger, but the rule itself does not mandate it explicitly.
Second, the interaction between ASR-related subsurface changes and spring discharge is not well characterized at the project scale in either authorized area, and spring systems are the primary habitat driver for the Eurycea species.
Third, the PAA changes under SB 1061 introduce a procedural shift that removes contested case hearing opportunities for certain Class III production area amendments. How that reduced public participation pathway will interact with related groundwater conservation concerns in the Edwards region remains to be seen.
The water supply need driving these rules is real. So are the biological and hydrogeological sensitivities in the areas where ASR is now authorized. Navigating that intersection carefully at the project level is where the work will be.