Las Vegas, NV Landscaping Rules: Rainwater Harvesting (2026)

Prior to 2017, Nevada's strict prior-appropriation water law technically made capturing rainwater an interference with downstream water rights. Nevada AB 138 (2017) reversed this for residential rooftop collection, expressly allowing single-family homeowners to harvest rainwater for non-potable outdoor uses — primarily landscape irrigation and decorative pond filling. Las Vegas imposes no additional permit requirements for standard residential rain barrels and small cistern systems. Collected water cannot be used for potable supply, cannot enter the plumbing system without cross-connection prevention, and cannot be sold. The practical limitation in Las Vegas is that annual rainfall averages only 4.2 inches, which produces roughly 2,600 gallons of collectable water per 1,000 sf of roof annually — modest but useful for container gardens and small xeriscape accents. Larger cistern systems (above a few hundred gallons) face structural-pad and setback review under the building code. Greywater reuse is a separate legal track (see below) and requires plumbing permits. Rainwater harvesting plus greywater stacking is increasingly used with SNWA turf-rebate landscape conversions to maximize water efficiency.