For new home builds, barndominiums, shops and land purchases outside the city sewer lines in East Texas — here's exactly how a legal, permitted installation works, and what to do first.
If the property connects to city sewer, you don't need any of this. If it doesn't, Texas law requires an OSSF — an on-site sewage facility — permitted before it's installed.
Every permitted installation in Smith and Gregg County follows the same sequence, set by TCEQ (the Texas Commission on Environmental Quality) and administered locally by TCEQ's authorized agent — usually the county. Skipping steps isn't a shortcut; an unpermitted system can surface at resale, refinance, or when the county catches up with the build.
A licensed site evaluator tests the soil (texture, drainage, seasonal water table) and maps the lot — setbacks from wells, property lines, water features and the house. This evaluation decides which system types your land can legally take. It's the single most important step: soil, not preference, picks the system.
Based on the evaluation and your home's bedroom count (which sets the required design flow), a system is designed — conventional drainfield, aerobic treatment unit, or another approved design — and the permit application goes to the authorized agent for approval. No digging before the permit issues.
A licensed OSSF installer sets the tank, builds the drainfield or treatment system, and the work is inspected — typically before anything is buried. Once it passes, the system is licensed for use and your build can proceed to final sign-off.
A complete new installation in Texas runs $6,300–$20,000. Where you land depends mostly on what your soil allows:
See the East Texas cost guide for the full breakdown of what moves the price.
Start the site evaluation before you finalize house plans or close on land. The evaluation can rule out a drainfield location you've already mentally built on, and permit timelines don't speed up because a builder is waiting. For land purchases, many East Texas buyers make the purchase contingent on a satisfactory site evaluation — ask your installer or agent about it.
Barndo builds often place the shop, living quarters and future additions on one lot. Tell the evaluator about future bathrooms and bedrooms now — designing the system for the finished property is far cheaper than replacing an undersized system in three years.
Send the project details and a licensed local installer will call you back to talk soil, system type and a real price for your lot.