Preliminary engineering reports and TCEQ design submittals for Texas wastewater plants

What it covers

The permit is not the design approval. A TPDES permit, a TLAP or a 210E authorization says what a plant may do. TCEQ's design rules for how it is built are in 30 TAC Chapter 217.

Under §217.6, the owner sends TCEQ a summary transmittal letter, sealed by the design engineer, for each plant and collection system project. TCEQ may then call for the full plans and engineering report. If TCEQ does not say in writing within 30 business days that it will review them, the project is conditionally approved. Under §217.10, the sealed engineering report carries every calculation and assumption that shows the design complies, and it is due within 30 days of TCEQ's written request.

The preliminary engineering report is where we set that basis first: flows, peaks, loads, phases, process and plant site. Final design, the submittal and the permit then tell the same story.

When you need one

• Your site cannot reach a sewer, and the permit path is chosen: a TPDES discharge permit, a TLAP or a 210E authorization.
• Your plant is filling up. Under 30 TAC §305.126, flow at 75% of the permitted flow for three consecutive months starts engineering and financial planning for expansion. At 90% for three months, you need TCEQ's authorization to build.
• You are altering or re-rating a plant. Under §217.34, its operating data become the design basis.

What we do

1. Build the flow from your program. §217.32 sets the method: per-person flows from Table B.1 times the people served, a factor of at least 1.5 below 1.0 MGD, and a peak of at least 4.0 times design flow without site data. Offices, restaurants and hotels each have their own rows. Process water needs its own characterization.
2. Set the phases. We size the final phase for buildout and lay out the site for it, then size the first phase for the first homes or tenants. The TCEQ technical report asks for Interim I, Interim II and Final, each with its own design flow and peak.
3. Site the plant. Under 30 TAC §309.13, plant units stay out of the 100-year floodplain unless protected, and most keep a 150-foot odor buffer to the property line or use an approved alternative. The plant, buffer and outfall or irrigation area go on the first concept plan.
4. Plan for the operator. Under 30 TAC §30.350, the permit holder must have licensed operators. We settle who will own and run the plant while we design it.
5. Prepare the report and the submittal. Calculations at your design flow, your peak and your waste, not a manufacturer's sheet. Then the sealed transmittal letter, and the full plans and report if TCEQ asks. We prepare it as the plant's engineer of record. When we design only a reuse system, the plant's submittal belongs to the plant's engineer.
6. Carry it into construction. We prepare the construction documents and can stay on for construction administration.

What you get

• A preliminary engineering report with flows, peaks and loads by phase, the process, the plant site and its buffer.
• The sealed summary transmittal letter for TCEQ, and the sealed engineering report and plans when TCEQ asks for them.
• Construction documents that match the report and the permit.

What affects time and cost

The program sets the flow. Firm unit counts, each non-residential use and any process water make the number defensible. A per-acre factor borrowed from another project invites questions.

Phasing adds work up front but avoids building tanks years before the flow arrives. Flow equalization, the site's floodplain and the odor buffer all change the layout. Choosing the permit path before design keeps the plant from being designed twice.

TCEQ presented proposed updates to Chapter 217 in October 2025, so we design to the rule in force when you build. TCEQ decides whether to review the plans, so we never promise an approval date.