Round Rock, TX Environmental Rules: Stormwater Management (2026)
Key Facts
- Minor storm design
- 25-year storm, curbs/gutters/sewers
- Major storm design
- 100-year storm, public drainage system
- Governing document
- Drainage Criteria Manual, Section 1
- Reviewing authority
- Engineering and Development Services Department
Summary
Round Rock requires all new drainage systems to handle the 25-year storm in curbs and storm sewers, with the citywide system built to convey up to a 100-year event.
B. Street curbs, gutters, inlets and storm sewers shall be designed to intercept, contain and transport all runoff from the 25 year frequency storm. C. In addition to B above, the public drainage system shall be designed to convey those flows from greater than the 25 year frequency storm up to and including the 100 - year frequency storm within defined public rights-of-way or drainage easements.
Full Breakdown
Round Rock's Drainage Criteria Manual, the city's adopted design standard under the Code of Ordinances, sets the storm-sizing rules for every subdivision and site plan. Street curbs, gutters, inlets and storm sewers must capture and carry the full 25-year storm, and the broader public drainage system, channels, easements, and rights-of-way, must be sized to pass the 100-year storm without flooding buildings or roadways. The Engineering and Development Services Department reviews and certifies drainage computations before construction plans, plats, or building permits are approved.
Violations & Fines
Plans that don't meet the 25-year/100-year storm standards are rejected by Engineering and Development Services; noncompliant construction can void plat approval and building permits.
Frequently Asked Questions
Does Round Rock require detention ponds for new development?
What storm event do Round Rock storm sewers have to handle?
Sources & Official References
Other rules in Round Rock
Texas rules heatmap·Compare Round Rock to another location·View the Texas environmental rules overview
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Stormwater Management in Nearby Cities
How other cities in Williamson County handle stormwater management.