Septic guide
Aerobic vs. Conventional Septic Systems
Why aerobic spray systems are so common around Conroe — and how they differ in upkeep and cost.
Conventional systems
A conventional system settles solids in a tank and lets the liquid drain through a gravel-and-soil drain field, where the soil does the final treatment. It’s simple and low-maintenance — but it only works where the soil actually drains.
Why aerobic dominates here
Much of Montgomery County has a sandy topsoil over a dense, slow-draining clay subsoil (a claypan). That clay won’t move effluent the way a conventional drain field needs, so many properties — especially on smaller lots — use aerobic treatment units instead.
How aerobic systems work
An aerobic unit adds oxygen to break down waste more completely, then disinfects and disperses the treated water, usually through spray irrigation across the yard. Because they treat to a higher standard, they can work where a conventional field can’t.
The maintenance trade-off
Aerobic systems have moving parts (an air pump, sometimes chlorination) and are legally required to stay under a maintenance contract, with an inspection reported to the county about every four months. They cost more to own over time than a conventional system, but on clay soils they’re often the only option that passes.