Do I need a permit to REPAIR an existing system, and what counts as repair vs alteration vs extension?

Yes — repair requires a permit, except for defined emergency repairs (replacing tank lids, inlet/outlet devices, risers and riser caps, disinfection devices, damaged drip tubing, solid lines), which must be reported in writing to the permitting authority within 72 hours after repairs begin (TCEQ, Getting a Permit for an OSSF). Under the rule definitions, "repair" means replacing any components of an OSSF in situations not covered by emergency repairs and excluding maintenance — and replacement of tanks or drainfields is a repair that requires a permit for the entire OSSF system; "alter" means a change producing increased permitted flow, changed influent, a departure from approved planning materials, a change in construction, or an increase/lengthening/expansion of the treatment or disposal system; "extend" means an alteration that increases capacity or lengthens/expands the existing system (30 TAC §285.2). Routine performance checks, cleaning, adjustments, and replacement of pumps, filters, aerator lines, valves, or electrical components are "maintenance," not alterations (30 TAC §285.2); Jackson County adds that adding bedrooms counts as an alteration under §285.2(2) (Jackson County OSSF guidelines).

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