Verified as of September 11, 2026. We re-check these pages quarterly.
The exemption exists
TCEQ allows an on-site sewage facility to be exempt from permitting — but only when every one of the following holds:
- The system complies with all other requirements, including the planning, construction and installation standards of 30 TAC 285
- The property has received a site evaluation conducted by a TCEQ-licensed Site Evaluator or a Professional Engineer
- It serves a single family dwelling
- On a tract of land that is 10 acres or larger
- It is not causing a nuisance and not polluting groundwater
- All parts of the system are at least 100 feet from the property line
- The effluent is disposed of on the property
- The single family dwelling is the only dwelling located on the tract
Where people fall out
The 100-foot setback. This is the one that fails most often. It is not the house that must be 100 feet from the line — it is every part of the system, which on a spray-disposal setup means the outer edge of the spray area. A ten-acre tract that is long and narrow can easily fail this while a square five-acre tract would not, if the acreage threshold were the only test.
The second dwelling. A guest house, a casita, a converted barn with a bathroom, a manufactured home for a family member — any of these can end the exemption. It says only dwelling on the tract, and it means it.
The site evaluation still happens. Exempt from permitting is not exempt from evaluation. You still need a licensed Site Evaluator or a PE to assess the ground. People read the exemption as permission to skip that step, and it is not.
The standards still apply. 30 TAC 285's planning, construction and installation standards apply either way. The exemption removes the permit, not the engineering.
The local authority can be stricter
This is the part that catches out anyone who researched the rule online and stopped there. TCEQ sets a floor. Local programs act as TCEQ's authorised agents and may impose requirements more stringent than the state minimum. A county is entitled to require a permit where the state would not.
So the only answer that protects you is the county's answer, in writing, for your specific tract.
What we suggest
If you are buying acreage and the seller says the system is exempt, treat that as a claim to be verified, not a fact. Ask for the site evaluation. Measure the disposal area to the nearest property line. Count the dwellings.
If you are building, get the site evaluation done early — it determines what kind of system is possible at all, which in this county is rarely a free choice.
Talk to us about a site evaluation · New system installation