Milwaukee, WI Landscaping Rules: Rainwater Harvesting (2026)

Under the Building and Zoning Code's drainage-of-roofs section, a rain barrel is defined as an above-ground prefabricated receptacle with an automatic overflow diversion system that collects and stores roof runoff. Rain barrels are permitted citywide provided the overflow discharge either meets the code's finished-grade discharge rules or is designed to overflow to a treatment drain or storm water conveyance system. Each barrel must be securely covered, fitted with an inlet screen, equipped with an overflow discharge device sized to adequately convey overflow to its discharge point, and built with a convenient, functional way to withdraw water. No separate rain-barrel permit is listed in this section.