Katy's minimum construction standards require storm sewers to contain a two-year storm without surcharging at minimum 0.1% gradient using Class III concrete pipe and follow Harris County PCPM hydrology standards.
Katy's Minimum Construction Standards supplement the subdivision development ordinance and define requirements for street, utility, and drainage construction in new subdivisions. Storm sewers must be sized so that a two-year storm is contained within the pipe without surcharging, with a minimum gradient of 0.1 percent or as approved by the city engineer, using Class III reinforced concrete pipe. Hydrology and methodology for the design of open channels and detention ponds must follow Harris County Flood Control District PCPM standards dated July 2019. Subdivision plats must show adequate drainage to reduce flood exposure. Lot grading must direct runoff away from structures and adjacent properties. The city engineer reviews all drainage plans.
Submitting plans that cause surcharging in a two-year storm, using non-conforming pipe, ignoring HCFCD PCPM design rules, or grading lots so runoff floods neighbors triggers plan rejection or enforcement.
See how other cities in Fort Bend County handle grading & drainage.
See how Katy's grading & drainage rules stack up against other locations.
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