Septic Systems
You need a permit before installing a septic system in Taylor County
Any property outside city sewer service in Taylor County that needs a septic system must get a permit and approved plan before construction begins.
In unincorporated Taylor County, homes that are not connected to a city sewer must use an on-site sewage facility (OSSF) — commonly called a septic system. Texas law requires a permit and an approved plan before you can install, alter, repair, or extend any OSSF. The permit process is managed locally under TCEQ rules.
You apply through the county's authorized agent. The site must be evaluated for soil type, lot size, and setback requirements before a design is approved. Installing a system without a permit is a violation. If you are buying rural land and plan to build, confirm septic feasibility early — some soils in West Texas do not perc well. Check TCEQ's OSSF permitting page for the state requirements.
Source to confirm: TCEQ — Getting a Permit for an OSSF (Septic System)