Tex. Water Code § 26.0405

(a) To the extent not in conflict with state water quality standards or federal law, the commission shall issue one or more general permits for the discharge of treated sewage into or adjacent to water in this state by a sewage treatment and disposal system if the system:

(1) produces not more than 5,000 gallons of waste each day;

(2) is in a county with a population of 2.8 million or more that is an authorized agent under Chapter 366, Health and Safety Code, and that has:

(A) adopted a resolution under Section 7.352 that authorizes the county to exercise enforcement power under Subchapter H, Chapter 7; and

(B) entered into an agreement with the commission to inspect, investigate, and otherwise monitor compliance with the permit;

(3) provides sewage treatment and disposal for a single-family residence for which the commission determines a connection to an existing or proposed area-wide or regional waste collection, treatment, and disposal system is not feasible; and

(4) is on a property that:

(A) was subdivided and developed before January 1, 1979; and

(B) is of insufficient size to accommodate on-site disposal of all wastewater in compliance with Chapter 366, Health and Safety Code.

(b) A person who discharges under a permit issued under this section is not required to hold a license or registration under Section 26.0301.

(c) For a permit issued under this section, the commission shall for each system:

(1) specify the design, operation, and maintenance requirements; and

(2) establish the primary and secondary treatment requirements.

(d) A system for which a permit is issued under this section is subject to design criteria established under Chapter 366, Health and Safety Code, and is not subject to design criteria established under Section 26.034.