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How A Septic System Works

On-Site Sewage Facility Management
For information on proper management of an on-site sewage facility, see the Williamson County Engineer's OSSF Care Guide. The OSSF Care Guide includes information on how to operate and maintain your OSSF.

Buying and Selling a House with OSSF
The mortgage guide includes information about buying and selling a home. It includes questions that a buyer or someone unfamiliar with an OSSF might ask. If you are aware of your system and active with management, you can give confidence to prospective buyers.

Re-Inspection of an Existing Residential OSSF:
Most mortgage lenders require a re-inspection of an OSSF whenever a property is sold. County Engineer's staff perform a surface inspection for this purpose. The Application for Evaluation of an Existing On-Site Sewage Facility form describes the scope and limitations of this inspection.

Aerobic Systems = More Requirements
There are some systems which require routine maintenance. Aerobic units treat wastewater well enough to be allowed some riskier disposal methods like surface application. Aerobic units are the most common way to treat wastewater for surface application disposal systems. They treat wastewater to a high quality but will need regular maintenance of the components to keep it working.

The State of Texas requires that these more complicated systems be maintained by requiring a maintenance contract with a licensed maintenance providers. To keep these systems working properly, owners will need to keep a contract in place with a valid maintenance provider. Maintenance providers will need to inspect and perform routine maintenance on the system in accordance with the contract. In addition to routine inspections, maintenance providers submit inspection reports to the County Engineer's office to document service and that the system is working properly. For more information about the function of maintenance providers see the TCEQ Maintenance of On-Site Sewage Facilities website. We have also included a guide to evaluating a service provider contract, see the Homeowner’s Guide to Evaluating Service Contracts.

With the proper training, owners who will live inside the home may be able to maintain their own aerobic systems. If you are interested in being your own aerobic system maintenance provider see the document Homeowner Maintenance Packet for more information.

The Williamson County Engineer's office permits these systems for two years. After the initial two-year contract with the system installation, a license renewal will need to be submitted to the Williamson County Engineer's office. Owners will need to submit new maintenance contracts, and renew their OSSF license with the Williamson County Engineer's office a minimum of every two years. The License Renewal/Transfer of License Form application must also be submitted when the property is sold and the license to operate needs to be transferred to a new buyer.