On-Site Sewage Facilities (OSSF)

Services We Provide

Williamson County's On-Site Sewage Facilities (OSSF) regulates On-Site Sewage Facilities (a.k.a. septic tanks) located within Williamson County, with the exception of those areas that are located within the City of Austin.

  • Permitting: Process permit applications and related fees for new and/or existing on-site sewage system
  • Inspections: Perform inspections as part of the permitting or complaint investigation processes
  • Complaint Investigation: Investigate exposed sewage and general public complaints related to OSSFs. Inherent to this activity are legal notices of violation and/or potential court action(s)
  • Program Information: Address general customer inquiries, including records information requests, permitting and fee process inquiries, technical inquiries on types of systems, and regulatory compliance questions.

Regulatory Authority

  • Williamson County Engineer's Office has been authorized by the Texas Commission on Environmental Quality to administer the On-site Sewage Facilities (OSSF) Program. The program falls primarily under the authority of TCEQ rules contained within 30 TAC Ch.285 On-Site Sewage Facilities
  • OSSF's installed and operated within Williamson County's jurisdiction must follow the requirement established in the Williamson County Engineer's On-Site Sewage Facility Rules

OSSF Open Records Requests

Open Records Requests can be submitted via email to the OSSF Department. Or visit our office and submit a completed Open Records Request (PDF) form to the front desk.

E-mailed Open Records Requests must include:

  • Requester's full name, email address, and phone number.
  • Full property address.
  • Description of information being requested.
  • Include property legal information if known (ex. Subdivision Name, Block, Lot).

How to Apply for a Permit

In an effort to provide better communication, document management and project tracking, Williamson County is now accepting OSSF applications through MyGovernment Online website. Our office is no longer accepting email or paper applications.

An application is required to modify an existing (i.e., repair or enlarge), or to install a new OSSF. Please select from a category below for more information:

How to Find out if My Property Require an on-Site Sewage Facility

Visit the County Address Search and enter the property address. If the City listed is "Unincorporated" or an ETJ is listed, it is likely that an OSSF is required. Call 512-943-3330 to verify.