Buying property with an unpermitted or undocumented septic system — exposure and how to fix it.

The permit runs with the property (it "transfers automatically to a new owner upon the sale or other legal transfer of an OSSF"), so a buyer inherits both the permit and any compliance problem (30 TAC §285.3). Exposure is real: TCEQ or the authorized agent may order a malfunctioning system repaired within 30, 20, or 10 days depending on prior notices, and the owner may be assessed administrative or civil penalties under Water Code Ch. 7 for each day it remains unrepaired (Tex. Health & Safety Code §366.017); constructing, altering, repairing, or extending another person's OSSF before the owner has the required permit is a Class C misdemeanor under Water Code §7.174 (Tex. Water Code §7.174), and one authorized agent states that failing to obtain a permit violates 30 TAC §§285.61(4) and 285.3(a) as a Class C misdemeanor of up to $500 per violation, with each day a new offense (NETMWD). To cure it, most agents offer a retroactive "existing system" path: Bexar County issues an Existing System Permit (Registration) when a system is found unpermitted, requiring a sanitarian or engineer to complete a site survey and septic design plus a pump manifest less than one year old (Bexar County); Williamson County charges the cost of the permit to inspect an unlicensed OSSF and requires the owner to purchase the appropriate permit and bring an illegal system into compliance (Williamson County); and Burleson County will search its records by address/property ID and verify the system is permitted and correctly sized before allowing a connection (Burleson County).

Reviewed August 2026. Links go to the sources this answer was checked against.