Merced County, CA Landscaping Rules: Water Restrictions (2026)

Outdoor water use in unincorporated Merced County is shaped largely by California state law, applied locally through the County's Water Efficient Landscape Ordinance. UDO Section 18.36.030 (WELO) states that all landscaped areas within the County must comply with Title 23 Section 2.7, the Model Water Efficient Landscape Ordinance (MWELO) of the California Code of Regulations as adopted by the State in 2015. MWELO applies to new and rehabilitated landscapes meeting size thresholds (generally 500+ sq ft for projects needing a permit/plan), caps turf, sets a water budget (Maximum Applied Water Allowance), and requires compost and at least 3 inches of mulch. Layered on top are California's permanent statewide water-waste prohibitions adopted by the State Water Resources Control Board: no using potable water to wash down sidewalks/driveways/hardscape, no irrigation runoff onto sidewalks or into gutters/storm drains, no watering outdoor landscapes within 48 hours of measurable (about a quarter-inch) rainfall, washing a vehicle only with a shutoff-nozzle hose, and no decorative fountains without recirculation. These apply countywide regardless of drought status. The County's own UDO landscape standards (Section 18.36.050) reinforce this by requiring at least 90 percent drought-resistant/well-adapted plant material and limiting turf to 30 percent of the landscaped area. Distinguish: WELO/MWELO and the SWRCB waste rules are state mandates; the County implements and enforces them.