Septic / OSSF
Septic Systems Outside City Limits in Webb County
If your home is outside the city limits of Laredo and not connected to a public sewer, you likely need a permitted on-site sewage facility (septic system).
A septic system — also called an on-site sewage facility, or OSSF — treats waste when there is no public sewer line. In Texas, you need a permit before you install one. The county or a local city usually issues the permit, not the state agency TCEQ directly. Call Webb County's environmental health office to find out who handles permits in your area.
Some older rural areas and colonias in Webb County have no public water or sewer at all. The TCEQ website explains what kinds of systems are allowed and how to keep them working. A broken or unpermitted system is a health risk. It can also mean legal trouble. If you are buying rural land in Webb County, ask if there is a permitted and working septic system before you close the deal.
Source to confirm: TCEQ – On-Site Sewage Facilities (Septic Systems)