Septic Systems in Williamson County Start With the OSSF Office

On many rural Williamson County lots, wastewater goes to a septic system instead of a city sewer line. The county On-Site Sewage Facilities program covers most of the county. The City of Austin is handled separately.

TCEQ authorizes the County Engineer's Office to run the program. State septic rules and county rules can apply to the same property. That matters on acreage, newly split land, and lots where the building footprint is changing.

An old tank is not permission for new work. Before closing on land or pouring a foundation, ask about applications, design, inspections, and any floodplain or certificate steps.