San Mateo County, CA Landscaping Rules: Water Restrictions (2026)
Water restrictions in San Mateo County, CA, also called the watering schedule, outdoor irrigation rules, or drought ordinance, set which days and hours you can run sprinklers or irrigation.
Key Facts
- Applies to
- Unincorporated San Mateo County only
- Governs
- New development & open-area landscape plans
- Citation
- Ordinance Code § 4.36.120
- Watering days
- Not set by this section
Summary
Unincorporated San Mateo County requires new-development and open-area landscape plans to build in water-saving design under Ordinance Code § 4.36.120: plant choice, irrigation efficiency and soil infiltration, not a fixed watering-day schedule.
Landscaping of new developments or of any open area, such as parks, playgrounds and golf courses, shall be planned to conserve water through choice of plants, landscape design, and irrigation techniques. It shall be the responsibility of the developer and the County to assure that the following water saving concepts are incorporated into landscape plans: evapotranspiration rates for different plantings, infiltration rates of applied water on different soil types and land areas with varying degrees of slope, and efficiency of application and distribution system to be used.
The development and utilization, within legal constraints of the following water saving techniques shall be encouraged with consideration given to the economics and aesthetics of the different situations:
a)Utilization of drought tolerant plants.b)Utilization of water application systems that are controlled to produce a high percentage of water application efficiency consistent with the needs of the given plant or plants in each situation (for example: drip irrigation systems, low delivery sprinkler nozzles, etc.).c)Utilization of reclaimed wastewater for irrigation when water quality, environmental, public health, and economic conditions Permit such use.d)Collection and reuse of run-off water where possible. (Prior code § 4161.1; Ord. 2681, 10/28/80)
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 47).
Full Breakdown
Ordinance Code § 4.36.120 requires landscape plans for new developments, parks, playgrounds and golf courses in unincorporated San Mateo County to conserve water through plant choice, landscape design and irrigation technique, with the developer and County jointly responsible for incorporating evapotranspiration rates, soil infiltration rates, and distribution-system efficiency into the plans. The section separately encourages, but does not mandate, drought-tolerant planting, high-efficiency irrigation such as drip systems, reclaimed wastewater use where feasible, and run-off collection. There is no fixed watering-day or watering-hour schedule set by this section.
Violations & Fines
No specific penalty is stated in this section; general Ordinance Code violations are punishable as a misdemeanor under § 1.08.010: a fine of up to $500 and/or up to six months in county jail.
Frequently Asked Questions
Does San Mateo County set specific watering days?
Does this rule apply inside Redwood City or other cities?
Sources & Official References
Other rules in San Mateo County
How San Mateo County compares: Cities with the Strictest Water Restrictions·California rules heatmap·Compare San Mateo County to another location·View the California landscaping rules overview
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