Texas groundwater availability certification for subdivisions (SB 2440), explained

Why Texas made groundwater certification mandatory

Rural subdivisions in fast-growing parts of Texas — especially the Hill Country west of Austin and San Antonio — often rely on individual domestic wells. Where lots are small and the aquifer is thin or slow to recharge, such as parts of the Trinity aquifer, wells can fail in drought and new homes can lower water levels in existing neighbors’ wells.

Counties and cities already had authority to require proof of groundwater availability before approving a plat, but few used it consistently. The 88th Legislature’s SB 2440 made the certification a mandatory part of plat applications for groundwater-supplied subdivisions, effective for applications filed on or after January 1, 2024.

What the law requires

• Scope — plat applications for subdividing a tract whose water supply source is groundwater under the land.
• Who certifies — a Texas-licensed professional engineer or licensed professional geoscientist.
• Form and content — as specified by TCEQ in 30 TAC Chapter 230 (Groundwater Availability Certification for Platting).
• Distribution — the applicant provides the certification to the municipal or county authority, the executive administrator of the Texas Water Development Board, and the applicable groundwater conservation district(s).
• Waivers — permitted only if the city or county finds, on credible evidence, that sufficient groundwater is and will continue to be available, and either the entire tract will be supplied from the Gulf Coast or Carrizo-Wilcox aquifer or the subdivision will have no more than 10 lots.

What goes into a groundwater availability certification

Chapter 230 lays out the information a certification must contain. In practice the work answers four questions about the specific tract:

• Demand — how much water the subdivision will use at build-out, based on the number of lots and expected use.
• Aquifer — which aquifer(s) underlie the tract and their thickness, properties and regional water-level trends, using existing records plus site-specific data such as a pumping test.
• Availability — whether wells can meet that demand over time, accounting for drawdown at each well and interference between neighboring wells as lots fill in.
• Quality — whether the groundwater meets drinking water standards or needs treatment.

Practical tips for developers

• Start early — a pumping test and analysis can take weeks, and the result can change lot layout or density.
• Check the groundwater conservation district — district spacing rules, permits and desired future conditions can constrain wells independently of the certification.
• Model the build-out, not the first well — availability problems usually appear as lots fill in and cones of depression overlap.
• Plan for drought — aquifers such as the Trinity and Edwards can fall quickly in dry years.
• Keep the data — well logs, test data and water-level records support later permits, lender reviews and HOA disclosures.

Frequently asked questions

HOW ARGOS HELPS

SOURCES

1. Texas Legislature — SB 2440 (88th Regular Session), enrolled bill text
2. TCEQ — Certification of groundwater availability for platting form (30 TAC 230)
3. TCEQ — Groundwater availability certification for platting rule adoption
4. Texas Alliance of Groundwater Districts — 88th Legislative wrap-up

Figures are taken from the primary sources above and dated as of the update shown. Concentrations are expressed in mg/L. Spot an error? Email support@argostellus.com.

RELATED GUIDES

• TEXAS GROUNDWATER

  Texas groundwater: the rule of capture, groundwater conservation districts and water availability

• WELL DRAWDOWN

  Cone of depression, drawdown and well interference, explained

• EDWARDS AQUIFER

  The Edwards Aquifer: J-17 levels, drought stages and pumping limits, explained

• DATA CENTER SITING

  Data center site selection: a groundwater availability due-diligence checklist