Brazoria County, TX Environmental Rules: Stormwater Management (2026)
Key Facts
- Governing manual
- Brazoria County Drainage Criteria Manual
- Design authority
- Drainage district engineer or County Engineering Dept.
- MS4 administrator
- Brazoria County Stormwater Quality Coalition
- State permits also required
- TCEQ TXR150000, TXR040000, TXR050000
- Non-compliance risk
- Development site shutdown
- County drainage liability
- None, except roads/streets
Summary
Unincorporated Brazoria County will not take responsibility for a subdivision's drainage beyond protecting its own roads. Developers must design drainage systems to the county's Drainage Criteria Manual, get sign-off from the applicable drainage district, and comply with the county's MS4 stormwater program or risk a shutdown.
A. Requirements 1. Responsibility for drainage will not be accepted by the County other than that accepted in connection with draining or protecting the road system and streets. 2. The drainage system shall be designed in accordance with the most recently adopted Drainage Criteria Manual, which is incorporated by reference as a part of these Subdivision Regulations or by the appropriate drainage district criteria manual. If a Subdivision is located within a drainage district, the Applicant's Engineer shall cooperate with the drainage district's Engineer in order to comply with its requirements. As evidence of this compliance, the Final Plat shall contain the signatures of the applicable drainage district commissioners. The system shall provide for drainage of Lots, streets, roads and other public areas as well as handling any run-off from adjacent areas that naturally flow into the subject area unless permitted by a drainage district. Runoff coefficients shall be based on completed projects.
Full Breakdown
" Every drainage system in a new subdivision must be designed to the most recently adopted Brazoria County Drainage Criteria Manual, which the regulations incorporate by reference, or to the criteria manual of the local drainage district if the tract sits inside one of the county's seven drainage districts. 11, Drainage System Authority). If a tract falls outside every drainage district, the County Engineering Department steps into the district's role and reviews the plat against the Drainage Criteria Manual itself. The designed system has to carry not just on-site runoff but any runoff from adjacent land that naturally flows onto the tract, unless a drainage district permits otherwise, and runoff coefficients used in the design must be based on completed projects rather than theoretical assumptions.
H requires every applicant to comply with Brazoria County's Municipal Separate Storm Sewer System (MS4) program, administered through the Brazoria County Stormwater Quality Coalition, on top of the state and federal TPDES permits (TXR150000, TXR040000, TXR050000) issued by TCEQ. The regulations warn that development sites can be shut down for failing to meet either the TPDES or the county's own stormwater requirements.
Violations & Fines
Failure to meet the Drainage Criteria Manual standards or get the required drainage district sign-off holds up plat approval outright. Sites that violate TPDES or the county's MS4 stormwater program requirements can be shut down. For broader noncompliance with the Subdivision Regulations, Section 1.08.C lets the Commissioners Court, through the District Attorney's Office, file a civil suit to recover the county's cost of bringing the project into compliance, and lets the county, the DA, or an affected property owner seek an injunction or abatement order in court.
Frequently Asked Questions
Does Brazoria County take over drainage maintenance in new subdivisions?
Which drainage standards apply to a project in unincorporated Brazoria County?
Can a stormwater violation shut down a construction site?
Sources & Official References
Other rules in Brazoria County
Texas rules heatmap·Compare Brazoria County to another location·View the Texas environmental rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.