Sumter County, FL Environmental Rules: Stormwater Management (2026)

Sec. 13-720 of the Land Development Code sets the county's baseline drainage and stormwater design standard. For an open basin, the minimum stormwater a development must retain on-site equals the difference between the predevelopment and post-development discharge rate for a 25-year, 24-hour storm event in Sumter County; for a closed basin, retention is calculated from the runoff volume less infiltration for a 100-year, 24-hour storm event. Sec. 13-720(b)(2) requires all new development and redevelopment to meet the water-quality treatment and disposal standards of applicable Florida Statutes and the Florida Administrative Code, following best management practices to cut pesticide, fertilizer and soil erosion runoff.

Sec. 13-720(e) bars a development from unreasonably burdening adjacent properties with surface water: it may not impede the natural predevelopment flow of water from neighboring land, nor channel water onto neighboring parcels at volumes that overload natural drainage or cause substantial damage, and post-development runoff rates, volumes and pollutant loads may not exceed pre-development conditions. Sec. 13-721(a)(3) separately makes it unlawful to discharge, or cause to be discharged, any pollutant into the county's stormwater drainage system that causes or contributes to a water-quality standard violation, other than stormwater itself; Sec.

13-721(a)(2) bars channeling surface water into sanitary sewers, sinkholes, wetlands or other water bodies without reasonable assurance the discharge meets state water quality standards. The county engineer approves the design, and site permits cannot issue until other state and federal drainage permits or exemptions are secured under Sec. 13-720(g).