Charleston, SC Landscaping Rules: Rainwater Harvesting (2026)

Sec. 32(1) of the Zoning Ordinance lists rainwater harvesting as one of the approved low-impact development systems, alongside bioretention cells, permeable pavement, stormwater infiltration, vegetated green roofs and impervious surface disconnection, that an Upper Peninsula District project can install to earn up to 2 stormwater management incentive points toward a height or density bonus. To qualify, the system must prevent at least 1 inch of stormwater runoff from discharging offsite, follow the design and maintenance recommendations of the city's Low Impact Development in Coastal South Carolina guide, and keep impervious surfaces at or below 65 percent of the site.

Owners must sign a recordable Maintenance and Operation Agreement requiring a yearly inspection and report by a South Carolina-licensed engineer, at the owner's cost, with any deficiencies corrected on a City-set timeline. A more specific rainwater harvesting requirement applies to the district's 'Quality Outdoor Public Space' incentive option under Sec. 32(6): to meet the 'Exceptional' tier of that option, the public space must use rainwater catchment cisterns to collect rainwater onsite, and the collected water must be reused in the space's irrigation system, with stormwater educational signage displayed in a prominent location.

Neither rainwater harvesting requirement is mandatory citywide; both are optional pathways to earn incentive points for buildings that opt into the Upper Peninsula District's height and density bonus program under Sec. 32.