Bexar County, TX Environmental Rules: Grading & Drainage (2026)

Although Bexar County cannot zone, it has broad authority to regulate subdivision plats and drainage under Texas Local Government Code Chapter 232 and the Texas Water Code. The Bexar County Commissioners Court has adopted a Drainage Policy and Subdivision Regulations requiring engineered drainage studies, detention for increased runoff, and conveyance sized for the 100-year storm event on new subdivision plats. Grading plans submitted with plat applications must demonstrate that post-development discharge does not exceed pre-development rates and that downstream properties are not adversely affected. On sites that are not part of a new plat, grading still triggers TCEQ stormwater permitting at the one-acre threshold and floodplain review where applicable. Development over the Edwards Aquifer Recharge Zone must comply with TCEQ Chapter 213 rules limiting mass grading, requiring pollution prevention BMPs, and capping impervious cover. Contractors must protect karst features, sensitive geologic zones, and existing trees consistent with the approved plan. Large grading projects in the Government Canyon State Natural Area vicinity and the San Antonio Hill Country rim are scrutinized closely.