Farmington Hills, MI Landscaping Rules: Rainwater Harvesting (2026)

Michigan does not have a statewide rainwater-harvesting law restricting residential collection, in contrast to Colorado's strict 110-gallon two-barrel cap. Under the Michigan Cost Effective Governmental Energy Use Act and general property-law principles, rainwater collection is legal across the state and is encouraged as a stormwater best-management practice. Farmington Hills does not regulate residential rain barrels under its municipal code: a homeowner may install one or more rain barrels on rooftop downspouts without a city permit for the barrel itself. Where a rain-barrel system connects to building plumbing or to an irrigation system tied into the potable supply, the Michigan Plumbing Code applies and a plumbing permit is required from the Farmington Hills Building Division. Cross-connections to the potable water supply are prohibited and must include an approved backflow-prevention device to comply with Chapter 33 of the City Code and EGLE's Safe Drinking Water Act administration. Larger cisterns and whole-house rainwater systems are subject to plumbing-code permit review. Farmington Hills' Reduce Flooding campaign expressly encourages rain barrels: 'Rain barrels are also a great way to reduce the amount of rain entering the Rouge River and provide the homeowner with free water for your yard and garden.' The Oakland County Water Resources Commissioner's RainSmart Rebates program is open to residents of southeast Oakland County and offers up to $2,000 per property for sustainable stormwater practices, including rain barrel installation, rain gardens, and tree planting. The Rouge River watershed and Farmington Hills' membership in the Alliance of Rouge Communities (ARC) make rain-barrel installation an actively promoted MS4 (Municipal Separate Storm Sewer System) compliance behavior under the City's NPDES permit administered by EGLE.