Edwards Aquifer Recharge Zone Development: What Austin Area Developers Must Do Differently for Wastewater

What is the recharge zone, and why does TCEQ treat it differently?

It is where the Edwards limestone reaches the surface, so water on the ground can reach the aquifer fast. Caves, sinkholes, faults and fractures in this karst rock give little filtering between a spill and the drinking water below.

TCEQ's rules in 30 TAC Chapter 213 set the goal that existing groundwater quality not be degraded. They cover eight counties, including Travis, Hays and Williamson, and split the land into the recharge, transition and contributing zones. The same section warns that local ordinances protecting water quality may also apply.

Start with the map. TCEQ's Edwards Aquifer Protection Program links to its map viewer, and since October 16, 2023 its Austin Regional Office has handled all Edwards applications. Near a zone boundary, have a geologist confirm what the map shows.

Which wastewater options does the recharge zone rule out?

A new surface discharge, and any disposal that relies on percolation. Under 30 TAC §213.6, new municipal and industrial discharges that would add pollutant loading are prohibited on the recharge zone, and so are increases to existing ones. 30 TAC §213.8 repeats the ban in its list of prohibited activities.

Land application that relies on percolation is prohibited too, except licensed private sewage facilities. Irrigation or evaporation systems are considered case by case and must reach at least secondary treatment. A new land application plant on the recharge zone may have no bypass and no discharge of untreated or partially treated wastewater.

So a discharge permit does not just face more scrutiny here. For a new plant on the recharge zone it is off the table, and the realistic paths are a sewer connection, an irrigation system that clears the case-by-case review, or reclaimed water reuse built on one of them.

What about discharges upstream of the recharge zone?

They are allowed but held to tighter effluent limits. New or increased discharges, other than industrial ones, within five miles upstream must meet 5 mg/L CBOD, 5 mg/L TSS, 2 mg/L ammonia nitrogen and 1 mg/L phosphorus as 30-day averages (§213.6(c)(1)).

From five to ten miles upstream, the rule sets a treatment level from Table 1 of 30 TAC Chapter 309, and TCEQ may require more case by case. Non-industrial discharges more than five miles upstream that reach certain Colorado River segments or Onion Creek follow 30 TAC §311.43 and §311.44.

What does an Edwards Aquifer protection plan require?

Approval before construction, built on a geologic assessment. Under 30 TAC §213.4, no one may start construction of a regulated activity until the plan is approved. TCEQ has 30 days to find an application complete or deficient and 90 days to review a complete one. Approval expires after two years unless more than 10% of the construction has begun.

The plan's contents are in 30 TAC §213.5:

• a geologic assessment signed and sealed by a geologist, mapping caves, sinkholes, faults, permeable fractures and other sensitive features (single-family subdivisions under ten acres are exempt);
• permanent stormwater controls that remove 80% of the added annual total suspended solids load from the project;
• controls that keep flow to naturally occurring sensitive features where practicable, since sealing or diverting that flow should be avoided;
• a licensed engineer's certification of the permanent controls after construction.

How do sensitive features shrink the usable site?

They take land out of the disposal and building areas. A tract that looks big enough for an irrigation field on gross acreage can come up short once the features are mapped and protected.

For septic systems the distances are fixed. Under 30 TAC §285.40, a new system on the recharge zone needs at least one acre per single-family dwelling, and no soil absorption system may sit within 150 feet of a recharge feature, or a tank within 50 feet. Other limits come out of the plan review and local rules, so get the geologic assessment before the site plan.

What changes for sewer lines and lift stations?

The collection system needs its own approved plan, testing and retesting. Under §213.5(c), a sewage collection system plan is approved before construction. New gravity lines of six inches or more and all new force mains are tested for leakage and certified by an engineer, then retested every five years.

Existing lines are tested for structural defects every five years, manholes built after March 21, 1990 must be watertight, and the geologic assessment covers the line route plus 50 feet on each side. Sewage holding tanks are prohibited in an organized collection system, except lift stations TCEQ approves (§213.8(a)(4)). Our post on lift stations and collection systems covers the design side, and the serving utility may add its own standards.

How does stormwater fit with the wastewater plan?

It is part of the same plan, so design them together. The 80% suspended solids requirement and the sensitive feature rules shape where ponds, water quality controls and disposal fields can go.

Off the recharge zone, the contributing zone has its own rule. Under 30 TAC §213.21, a regulated activity disturbing five acres or more, or less as part of a larger common plan, needs an approved contributing zone plan before construction.

Before you commit to a wastewater strategy, run this check. Every answer should be yes:

1. Have you confirmed the zone (recharge, transition or contributing) from TCEQ's maps, with a geologist near a boundary?
2. Does your strategy avoid a new discharge and percolation-based disposal on the recharge zone?
3. Is the geologic assessment done before the site plan?
4. Have the sensitive features been subtracted from the disposal and building areas?
5. Does the plan include a collection system plan with testing and five-year retesting?
6. Are stormwater controls and disposal areas laid out together?
7. Have you asked the city and the serving utility about their own rules?

Any no is a question for your engineer and geologist before you close.

This post is general education on TCEQ's Chapter 213 and related rules as published in October 2026. TCEQ decides each plan and permit, and local rules may add more, so confirm the current requirements with your engineer.

Frequently asked questions

How do I find out whether my Austin-area parcel is on the recharge zone?

Start with TCEQ's Edwards Aquifer map viewer, linked from the program page, before you sign a purchase contract. Near a boundary, have a geologist confirm the designation on the ground.

Can I use a land application permit on the recharge zone?

Irrigation or evaporation systems are reviewed case by case and need at least secondary treatment. Systems that rely on percolation are prohibited, except licensed on-site sewage facilities.

I'm planning a large-lot subdivision in southwest Travis County on the recharge zone. Can each lot use its own septic system?

Possibly. Under §285.40 a new system needs at least one acre per single-family dwelling and must keep its soil absorption system 150 feet from any recharge feature. Travis County's own rules and the Edwards Aquifer protection plan apply too.

I'm an engineer on a Hays County project a few miles upstream of the recharge zone. What effluent quality should I plan for if we discharge?

Within five miles upstream, plan on 5 mg/L CBOD, 5 mg/L TSS, 2 mg/L ammonia nitrogen and 1 mg/L phosphorus as 30-day averages. From five to ten miles, the rule sets a treatment level from Chapter 309, Table 1, and TCEQ may require more case by case.

How long does TCEQ take to review an Edwards Aquifer protection plan?

By rule, 30 days to find it complete or deficient and 90 days for technical review of a complete plan. Deficiency responses add time, and approval expires after two years without substantial construction.

Related resources

• I-35 Corridor Development Wastewater Feasibility: How to Avoid the Most Common TCEQ Errors in Hays County
• OSSF vs. Centralized Sewer: Choosing Between Travis County Septic Permitting and TCEQ Wastewater Permits for Exurban Sites
• Texas Land Application Permits Explained: Spray Irrigation, Subsurface Drip, and Evaporation Ponds
• Austin Water Service Extension Requests: Who Pays for Off Site Water, Wastewater, and Reclaimed Water Improvements?

Planning wastewater for a site on the Edwards recharge zone?

We work through the zone, the features and the disposal options with your geologist during due diligence, so the site plan fits what the rules allow.

We specialize in:

• Site feasibility and due diligence
• Wastewater treatment and land application design
• TCEQ wastewater permitting
• Lift station and collection system design
• Stormwater and site civil design
• Construction administration

Modern Engineering Solutions, McKinney, Texas. Contact: (214) 833-6748 or mod-eng.com