Austin, TX Fence Regulations: Retaining Walls (2026)

Under the 2021 International Residential Code as adopted by Austin (Chapter 25-12), retaining walls up to 4 feet in exposed height and not supporting a surcharge are exempt from a building permit but must still comply with zoning setbacks and impervious-cover rules. Walls over 4 feet or any wall supporting a sloped surcharge (within a 1:1 angle from the base) require signed engineered drawings from a Texas PE and a building permit ($350+ with plan review). In Critical Water Quality Zones (CWQZ) of Barton Creek, Bull Creek, Onion Creek, Shoal Creek, and other Hill Country watersheds, the Watershed Protection Department imposes additional review — walls near creeks need Environmental Review and sometimes a variance. Cuts and fills exceeding 4 feet trigger the Hill Country Roadway Ordinance in designated corridors. Terracing (multiple short walls with plantable benches) is preferred for steep lots and often avoids engineering fees. Drainage outlets must not concentrate flow onto neighboring property. Non-permitted walls that fail and damage neighbors expose owners to negligence liability.