Rockville, MD Landscaping Rules: Rainwater Harvesting (2026)

Rainwater harvesting is legal and actively encouraged in Rockville. The city's RainScapes Rebate Program provides financial incentives for residents who install rain barrels, cisterns, and other stormwater capture systems on eligible properties. Rebates of up to $5,000 lifetime maximum are available for qualifying installations. Standard rain barrels connected to residential downspouts do not require a city permit. Larger cistern systems that qualify as accessory structures may require a building permit review under the zoning ordinance. Maryland Department of the Environment stormwater design guidance recognizes rainwater harvesting as an approved best management practice (BMP) for meeting stormwater management requirements. The city is located in the Chesapeake Bay watershed, where stormwater management is a high priority, and rainwater capture directly reduces pollutant loads reaching local waterways including Rock Creek and the Potomac River. Indoor use of harvested rainwater is typically limited to non-potable applications such as toilet flushing, cleaning, and laundry. Connection to the potable water system requires backflow prevention devices and may require approval from WSSC Water. Montgomery County's DEP also offers complementary RainScapes resources and technical assistance for water harvesting installations.