Brazoria County (Unincorporated)
Brazoria County Engineering Department
CountyMS4 Phase IIVerified 2026-03
Local Permit / Authorization
- Permit Required
- Yes
- Permit Name
- Drainage Permit / Floodplain Development Permit
- Submit To
- Brazoria County Engineering Department
- Lead Time
- Plan review typically 2–4 weeks
- Application Method
- Submit via Brazoria County Engineering at 111 E. Locust St., Angleton, TX 77515 or online portal; Brazoria County Drainage District permits required separately
- Fee
- Contact agency for current fee schedule
Water Quality Standards
- Impervious Cover Limit
- No countywide impervious cover cap; drainage systems must accommodate design storm flows per Brazoria County Drainage Criteria; multiple drainage districts operate within the county
- On-Site Treatment Required
- No
- Detention Required
- Yes
- Detention Standard
- Detention required to limit post-development peak flows to pre-development levels for 2-, 10-, 25-, and 100-year storms per Brazoria County and applicable Drainage District criteria; post-Harvey design standards updated; flat coastal plain terrain requires conservative detention sizing
- Turbidity Standard
- No numeric NTU limit; discharges must comply with TCEQ TXR150000 and not degrade Brazos River, San Bernard River, Chocolate Bayou, or Galveston Bay tributaries
Local SWPPP / Drainage Plan
- Local Plan Required
- Yes
- Plan Name
- SWPPP per TCEQ TXR150000; drainage report required for county permits
- PE Stamp Required
- Yes
Drainage study prepared by a Texas PE required for development permits. Brazoria County has over 20 drainage districts, each with independent permit authority over their maintained channels. A project may need permits from both Brazoria County Engineering and the applicable drainage district. Post-Harvey drainage improvements are ongoing throughout the county. The Brazos River diversion project (completed near Freeport) has altered some regional drainage patterns.
Local Inspection Requirements
- Requirements
- Brazoria County Engineering inspects county-permitted development; drainage districts inspect work adjacent to or connecting to their channels. Hurricane season requires active BMP maintenance.
- Inspector Qualification
- No county-specific certification required beyond TCEQ SWPPP requirements
Special Overlay Zones
Brazos River Floodplain
Trigger: Development within FEMA-mapped 100-year floodplain along the Brazos River (Texas's longest river), which drains to the Gulf through Brazoria County
Restriction: Floodplain development permit required; USACE Section 404/10 permits required for work in or adjacent to the Brazos; major flooding events have reshaped floodplain mapping
Brazoria County Drainage Districts
Trigger: Development in areas served by Brazoria County Drainage Districts (BCDD1–BCDD3 and others)
Restriction: Each drainage district has independent permit authority; outfall connections to district channels require district approval; district design criteria may exceed county minimums
Galveston Bay TMDL Watershed
Trigger: Development draining to tributaries of Galveston Bay, which has established TMDLs for bacteria and nutrients
Restriction: Enhanced water quality controls required; Galveston Bay Foundation and TCEQ monitor bay water quality; sediment, nutrients, and bacteria controls are priority pollutants
Coastal Zone / Gulf Coast Proximity
Trigger: Development in Brazoria County's coastal areas near the Gulf of Mexico or Freeport area
Restriction: Texas General Land Office (GLO) Coastal Management Program may apply; dune protection areas require GLO permit; USACE wetland permits likely required in coastal lowlands
Design Manual
- Manual Name
- Brazoria County Drainage Criteria
Official Resources
Jurisdiction Notes
Brazoria County occupies the coastal plain southwest of Houston, encompassing Pearland (northern), Angleton (county seat), and the Gulf Coast at Freeport/Surfside. The county is intensely agricultural and industrial, with significant petrochemical facilities at Freeport. Hurricane Harvey caused catastrophic flooding throughout the county. The Brazoria County Drainage District system is extensive, with multiple independent districts each having their own permit authority. The county is experiencing strong growth pressure from Houston's southward expansion. The Brazos River mouth at Freeport is a key hydrologic feature.
Remember: These local requirements are in addition to the TCEQ state construction permit. Both must be satisfied before breaking ground.
Disclaimer: This information is provided for general reference only. Always verify requirements directly with Brazoria County Engineering Department and the agency website before beginning construction.