Septic guide
Septic Permits in Montgomery County, TX
How on-site sewage (OSSF) permitting works here — who issues them, when you need one, and the Lake Conroe exception.
Who issues the permit
In Montgomery County, septic systems (officially “on-site sewage facilities,” or OSSFs) are permitted and inspected by Montgomery County Environmental Health Services, which acts as the local authorized agent for the Texas Commission on Environmental Quality (TCEQ). Neighboring counties run their own programs — Harris County for parts of Spring and Tomball, Walker County for Huntsville, and Liberty County around Cleveland.
When you need one
A permit and an approved plan are required to construct, alter, repair, or operate a system. The process starts with a soil and site evaluation by a TCEQ-licensed site evaluator or professional engineer, which determines what kind of system the property can support.
Lot size rules
A minimum lot size of about 1.5 acres generally applies when a property uses both a septic system and a private water well. Single-family homes on tracts of roughly 10 acres or more may be exempt from the permit requirement if they still meet construction standards — but the standards themselves don’t go away.
The Lake Conroe exception
Systems within 2,075 feet of Lake Conroe are permitted by the San Jacinto River Authority (SJRA) rather than the county, and carry extra design, inspection, and maintenance requirements. Lakefront subdivisions like Walden, April Sound, and Bentwater fall under these rules.
Aerobic systems need ongoing paperwork
If your system is an aerobic treatment unit, Texas rules require a maintenance contract, with an inspection reported to the permitting authority about every four months. That’s a permanent obligation, not a one-time step.