Costa Mesa, CA Landscaping Rules: Water Restrictions (2026)

Chapter VII of the zoning code, sections 13-101 through 13-108, sets Costa Mesa's landscape water conservation standards under the state's Model Water Efficient Landscape framework, and section 13-107 holds the irrigation-specific requirements. Any landscaped area on a commercial or industrial site, or on a residential site with more than two dwelling units, must have an approved, automatically time-controlled sprinkler system rather than manual watering. The irrigation and drip system itself must use underground piped water lines with low-flow sprinklers, drip or trickle emitters as specified in the city's water efficient landscape guidelines, sized so water meter and line capacity covers both irrigation and building demand together.

Because shrubs and turf have different watering needs, the code requires separate control valves or emitter heads whenever both appear on the same landscape plan, and the whole system must be designed so overspray, runoff and low-head drainage onto streets, sidewalks, windows, walls and fences are minimized, with automatic watering cycles timed to maximize ground infiltration. Section 13-107(c) defers actual watering schedules to the applicable water district's requirements rather than setting citywide days or hours. The heaviest-duty mandate applies to larger sites: any irrigation system serving a project of one acre or more must run on reclaimed water whenever the applicable water agency has it available, subject to that agency's health-standard review.

Ongoing compliance falls to the property owner under section 13-108, which requires routine irrigation repair and adjustment, scheduling tied to the California Irrigation Management Information System, and use of moisture-sensing or rain shut-off devices as part of required landscape maintenance.