How Often Must an Aerobic System Be Inspected in Texas?

A Texas aerobic treatment system must be tested and inspected at least once every four months, which is three visits per year. The requirement is in 30 TAC §285.91(4), Table IV, which sets the testing frequency for “Any Treatment Method in Conjunction with Surface Application” and “Any Secondary Treatment System” at “At least once every four months.”

The frequency can be reduced to two tests per year under 30 TAC §285.7(e)(3) when the system has “electronic monitoring and automatic telephone or radio access that will notify the maintenance provider of system or components failure and will monitor the amount of disinfection in the system.” The provider must keep that monitoring working.

Each visit includes the component inspection in Figure 3 (30 TAC §285.90(3)), the Table IV tests, marking the tag (§285.7(e)(2)), and a report to the permitting authority and owner within 14 days (§285.7(e)(1)(B)). Local authorities may require more.

Summarizes public rules as of Oct 5, 2026; not legal advice; verify with your permitting authority.

Where does the four-month rule come from?

Two sections work together. 30 TAC §285.7(e)(1) says the maintenance provider “shall test and report for each system as required in §285.91(12) of this title.” Table XII in §285.91(12) identifies which system types need testing and reporting, and footnote (2) of that table sends you to §285.91(4) for the frequency. Table IV then sets the schedule.

Type and size of treatment unit (Table IV)	Testing frequency	Required tests	Minimum acceptable result
Any treatment method with surface application	At least once every four months	Total chlorine residual or fecal coliform at each required test; one BOD5 and TSS grab sample per year (non-single-family only)	0.1 mg/l residual in pump tank, or fecal coliform not to exceed 200 MPN/100 ml; BOD5 and TSS not to exceed 65 mg/l
Any secondary treatment system	At least once every four months	None	None
Non-standard	Permit specific	Permit specific	Permit specific

Source: 30 TAC §285.91(4), Table IV.

Two things stand out in the table. The four-month interval applies to both surface-application systems and secondary treatment systems with subsurface disposal (drip, drainfield, mound, and so on). The difference is what you test: surface-application systems carry a chlorine residual or fecal coliform test; secondary treatment systems with subsurface disposal have no required laboratory or field test, but the visit, the component inspection, and the report still happen.

When can a system drop to two visits a year?

30 TAC §285.7(e)(3):

“The number of required tests may be reduced to two per year for all systems having electronic monitoring and automatic telephone or radio access that will notify the maintenance provider of system or components failure and will monitor the amount of disinfection in the system. The maintenance provider shall be responsible for ensuring that the electronic monitoring and automatic telephone or radio access systems are working properly.”

To qualify, the monitoring has to do two jobs: notify the provider of a system or component failure, and monitor the disinfection level. An alarm light by itself does not meet that text. The rule says the number of tests “may be reduced,” which leaves the permitting authority room to require three visits anyway, and the maintenance contract must state the frequency actually used (§285.7(d)(1)(D)). Document the monitoring equipment on the contract and in the permit file before moving a system to a two-visit schedule.

What counts as an inspection or test?

The rule describes a “maintenance check and test” through three documents:

• Figure 3, Sample Testing and Reporting Record (30 TAC §285.90(3)) lists the inspection items: aerators, filters, irrigation pumps, recirculation pumps, sludge condition, disinfection device, chlorine supply, electrical circuits, distribution system, sprayfield vegetation/seeding (if applicable), and “other as noted.” Each is marked operational or inoperative. The form also records repairs, whether access ports were secured, test results, complaint responses, and comments.
• Table IV (30 TAC §285.91(4)) lists the tests and acceptable results shown above.
• The tag (30 TAC §285.7(e)(2)) must be “either punched or indelibly marked with the date the system was checked at the time of each maintenance check, including any maintenance check in response to owner complaints.”

A visit that skips the component check or the required test is not a complete inspection under the rule, even if a report is filed.

Can the owner skip inspections after two years?

A single-family owner who elects to maintain the system personally under 30 TAC §285.7(d)(4) “is not subject to testing and reporting requirements” (§285.7(e)(4)). That exemption belongs to the owner, not to a contracted provider. While a maintenance contract or initial two-year service policy is in force, the full schedule applies. See Can homeowners maintain their own aerobic system in Texas?.

Can a county require more than three visits?

Yes. 30 TAC §285.3(a)(1) states that all aspects of OSSF operation and maintenance “shall be conducted according to this chapter, or according to an order, ordinance, or resolution of an authorized agent,” and TCEQ’s maintenance page notes that “Some permitting authorities have adopted more stringent requirements.” Check the county or river authority order for its inspection interval, any extra test items, and any restriction on the two-visit electronic-monitoring option. The permitting authority or TCEQ may also inspect an aerobic system at any time under §285.7(g).

Sources

• 30 TAC §285.91, Tables (Table IV, Table XII): https://www.law.cornell.edu/regulations/texas/30-Tex-Admin-Code-SS-285-91
• 30 TAC §285.7, Maintenance Requirements: https://www.law.cornell.edu/regulations/texas/30-Tex-Admin-Code-SS-285-7
• TCEQ, Maintenance of On-Site Sewage Facilities: https://www.tceq.texas.gov/permitting/ossf/ossfmaintenance.html

Last verified: 2026-10-05. Summarizes public rules as of Oct 5, 2026; not legal advice; verify with your permitting authority.

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