Septic / OSSF
Septic Systems in Tarrant County Require a Permit
If your Tarrant County property is not on a public sewer, you need a county permit for any new or substantially changed on-site sewage system.
Tarrant County oversees septic systems — also called on-site sewage facilities, or OSSF — in areas without public sewer. This covers unincorporated areas and 23 cities. To put in a new septic system, you file an application, let the county check your site, and get a permit. Call the OSSF office for current permit fees.
A rule adopted in November 2025 says lots with a septic system must be at least one acre. That acre is measured after taking out drainage areas and floodplain land. Most unincorporated Tarrant County land also falls inside a city's planning zone. That means city rules may apply on top of county rules. Before you build or buy a lot without public sewer, call the county OSSF office at 817-212-7082.
Source to confirm: Tarrant County – On-Site Sewage Facilities