Montgomery County, MD Landscaping Rules: Rainwater Harvesting (2026)

Maryland law explicitly permits residential rainwater harvesting. Montgomery County actively encourages it through the RainScapes Rebates Program administered by the Department of Environmental Protection (DEP). Standard rain barrels (up to 80 gallons) require no permits and are available at discounted rates through county and WSSC partnerships. The RainScapes program provides rebates up to $2,500 for more extensive installations including rain gardens, cisterns, conservation landscaping, permeable pavers, and green roofs. Cistern systems over 250 gallons may require DPS plumbing permits and WSSC backflow prevention review if connected to indoor plumbing. Collected rainwater may be used for irrigation, car washing, and non-potable outdoor purposes. Maryland Environment Article does not restrict rainwater collection as some western states do. The county credits stormwater management fee reductions for properties with approved rainwater harvesting systems. Commercial properties with large cisterns may qualify for Water Quality Protection Charge (WQPC) credits.