San Mateo, CA Landscaping Rules: Native Plants (2026)

About 40% of the water Californians use at home is used outdoors. Large water savings can be gained by efficient landscape design, installation, management, and maintenance. This is accomplished by choosing climate adapted plants, improving soil conditions, using, and maintaining high efficiency irrigation equipment and managing the irrigation schedule to fit the plants water needs as they are influenced by local climate. To increase water efficiency and better use a valuable resource, rainwater and stormwater collection and graywater and recycled water can replace or augment potable water use in landscapes. New development and retrofitted landscape water efficiency standards are governed by the Model Water Efficient Landscape Ordinance (MWELO) . The MWELO is also referenced by Title 24, Part 11, Chapters 4 and 5 CalGreen Building Code. All local agencies must adopt, implement, and enforce the MWELO or a local Water Efficient Landscape Ordinance (WELO) that is at least as effective as the MWELO. Usually, local agencies that adopt WELOs create a more stringent ordinance than MWELO. The purpose of water efficient landscape ordinances is to not only increase water efficiency but to improve environmental conditions in the built environment. Landscaping should be valued beyond the aesthetic because landscapes replace habitat lost to development and provide many other related benefits such as improvements to public health and quality of life, climate change mitigation, energy and materials conservation and increased property values.