How Mixed-Use Developments Qualify for 210E Even When 90% of Their Flow Is Residential

What does Chapter 210 say about mixed industrial and domestic flow?

It defines the mix and makes it eligible for Level II, with no percentage attached. 30 TAC §210.52 defines industrial wastewater as "a non-domestic or non-municipal wastewater." It defines commingled wastewater as industrial wastewater "that contains any amount of domestic wastewater."

§210.53(b) lists five ways to be eligible to apply for Level II. Paragraph (2) is industrial reclaimed water that contains any amount of domestic wastewater. Nothing in the section sets a minimum industrial flow, a minimum share or a ratio.

The text is silent the other way too. It does not say when a stream that is mostly homes stops being industrial wastewater with some domestic flow in it. TCEQ decides how your stream is classified, which is one more reason to raise it before you file.

What changes once domestic wastewater is in the stream?

The industrial-only exemptions fall away, and the domestic reclaimed water rules come in. Under §210.56(a)(1), paragraphs (2) through (6) of that subsection "do not apply to commingled water."

Paragraph (3) is the one developers hear about. It says a producer, provider or user of industrial reclaimed water "is not required to treat industrial water or hold a permit for treatment and disposal." For commingled water, that waiver is off the table.

Instead, the commingled stream "is subject to all requirements of" §§210.1 to 210.9, 210.21 to 210.25 and 210.31 to 210.36. Among them:

• the reclaimed water quality standards in §210.33, set by Type I or Type II use;
• sampling and analysis under §210.34, and records and reports under §210.36;
• the storage, irrigation and design rules in §§210.23 to 210.25;
• §210.2(e), which says a producer of reclaimed water must obtain a TPDES permit, a Texas Land Application Permit (TLAP) or a Chapter 321, Subchapter P authorization before construction and operation of the treatment facility.

The Level II limits in §210.56(d) still apply on top: total organic carbon of 55 mg/L, sampled monthly by grab, and pH between 6.0 and 9.0, sampled weekly by grab. Ask TCEQ early which authorizations your plant needs, before final design.

What counts as an eligible industrial component?

Non-domestic wastewater that §210.54 does not exclude. The exclusions in §210.54(a) apply "regardless of effluent quality or end use." They include process wastewater regulated under 40 CFR Parts 400 to 471, except a short list of categories, and septic tank, grit trap and grease trap waste.

Uses that often show up in a mixed-use program:

• Data center cooling. Cooling tower blowdown is non-domestic wastewater. Blowdown under 2,000 mg/L of total dissolved solids is even on the Level I list in §210.53(a)(8) when used on site alone. Mixed with domestic flow, it goes to Level II.
• Food and beverage. Section 210.54 allows some federal food categories, including dairy products, grain mills, canned and preserved fruits and vegetables, and sugar processing. Meat and poultry processing is not on the allowed list.
• Light manufacturing. Check the facility's federal category first. Most categories in Parts 400 to 471 are excluded; cement manufacturing (Part 411), soap and detergent manufacturing (Part 417) and a few others are allowed.
• Concrete batch plants. Check this one with TCEQ. Section 210.54(a)(9) excludes any wastewater for which a Chapter 321 permit by rule or a commission-issued general permit for land application is available. Ready-mixed concrete plants have TCEQ's general permit TXG110000, which covers discharges "into or adjacent to water in the state" and on-site irrigation. The 2021 issue expires in November 2026, so check the current version.

The test is the waste stream, not the label on the building. A tenant that sounds industrial may produce excluded process water, while a modest cooling system may fit cleanly.

Our 210E reuse project near Martindale, Texas shows the mix: a master-planned development with homes, data center operations and a concrete batch plant, and treated water reused for off-site agricultural irrigation. Each non-domestic stream in a program like that still gets its own §210.54 check.

Does a 90 percent residential share rule a project out?

Not by any percentage in the rule. Section 210.53(b)(2) says "any amount," and neither §210.53 nor §210.56 sets a ratio.

What the share does change is design. The plant treats the whole combined stream to the Level II limits and to the §210.33 standard for the use. So the residential flow drives most of the treatment, storage and irrigation sizing.

A small industrial use does not make a large residential plant simpler. Most of the design work sits in the domestic rules in Subchapters A to C.

When should a mixed-use developer run this check?

Before the land plan and the tenant program are fixed. If the program already includes a data center pad, a food or beverage tenant or light industrial space for market reasons, check those waste streams against §210.54 early. If the reuse plan depends on one, that tenant has to arrive on the schedule the plant needs.

Compare the other routes at the same time. A private plant under its own TPDES permit or TLAP goes through technical review, public notice and a possible contested case hearing. Our post on permit by rule vs. standard permit explains why no shortcut permit covers a development's sewage, and our 210E authorization work starts with the classification question.

Answer each question yes or no. Any no is something to settle with your engineer and TCEQ before design:

1. Is there a specific non-domestic waste stream whose source you can describe in the application (§210.55(b)(6))?
2. Have you checked that stream against every exclusion in §210.54(a), including the general permit and permit by rule test in paragraph (9)?
3. Will the industrial user be operating when reuse begins, so the effluent testing reflects the real combined stream?
4. Has TCEQ said how it will classify your combined stream?
5. Has TCEQ said which authorizations the treatment plant needs under §210.2(e)?
6. Do you have a primary disposal method for water you cannot reuse (§210.55(b)(7))?
7. Is there enough irrigated area and storage for the full combined flow, including wet weather?

This is general education on 30 TAC Chapter 210 as published in October 2026, not advice on a specific site. TCEQ proposed a change to §210.54 in May 2026 that would add produced water to the allowed process categories; check the current text before you file. TCEQ decides how a stream is classified and what a plant needs, so confirm the path with TCEQ and your engineer.

Frequently asked questions

Is there a minimum industrial flow for a 210E Level II authorization?

No minimum appears in §210.53(b)(2). The industrial stream still has to pass §210.54, and the commingled stream carries the Subchapter A to C rules.

Does a commingled 210E plant also need a TPDES permit or TLAP?

Settle it with TCEQ before design. The §210.56(a)(3) waiver of a treatment and disposal permit does not apply to commingled water. Section 210.56(a)(1) applies §210.2(e) instead, which calls for a TPDES permit, TLAP or Subchapter P authorization before the treatment facility is built and operated.

I'm planning a master-planned community in Bastrop County with a data center pad on one corner. If the data center's cooling water joins the neighborhood sewer, can the whole plant go under a 210E?

Possibly, as commingled water under a Level II authorization. The whole stream would then carry the domestic reclaimed water rules too, including §210.2(e). Ask TCEQ how it classifies the stream and what the plant needs before you size it.

I'm a civil engineer on a Texas mixed-use project, and the industrial tenant will not open until phase 2. Can we file the 210E application before the tenant is operating?

The application has to describe the waste source and include effluent testing results (§210.55(b)(6) and (9)). Until the tenant operates, there is no industrial stream to test. Raise phasing with TCEQ before you file, and plan how phase 1 flow is handled in the meantime.

Which industrial wastewaters can never go under 210E?

Section 210.54(a) lists them. Among others: radioactive, dioxin, pesticide and hazardous wastewater; most federally categorized process wastewater; septic, chemical toilet, grit trap and grease trap waste; barge cleaning and air scrubber wastewater; and wastewater with a permit by rule or land application general permit available.

Related resources

• What Is a 210E Authorization and How Can It Save Your Texas Development Project?
• 210E vs. TPDES Discharge Permit: A Side-by-Side Comparison for Developers
• What Happens to Your 210E Permit When Your Industrial Tenant Leaves?
• 210E Authorization Compliance: Why “No Expiration” Doesn’t Mean No Deadlines for Texas Developers

Planning a mixed-use project around a 210E authorization?

We check the waste streams, the tenant program and the reuse area against Chapter 210, and take the permit path question to TCEQ before design starts.

We specialize in:

• 210E and Chapter 210 reuse authorizations
• TCEQ wastewater permitting
• Wastewater treatment and reuse system design
• Reuse area, irrigation and storage design
• Utility feasibility for land development
• Construction administration

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