Landscaping Rules in Costa Mesa, CA: What Residents Actually Need to Know

If you live in Costa Mesa or are thinking about moving there, landscaping rules are one of those things you probably won't think about until they affect you directly. Costa Mesa has 7 specific rules on the books covering different aspects of landscaping rules, and some of them might surprise you.

Tree Removal & Heritage Trees

Costa Mesa bans removing or destroying any tree in a required landscaped area without prior city approval. Property owners must submit site plans showing existing and replacement trees, plus a written request and justification, to the planning division. The division can demand a report from a California-licensed arborist before signing off, and replacement trees must match the size of what's removed.

Key details: Governing section: Costa Mesa Municipal Code § 13-108(c). Approval required: Written request, site plan, city approval before removal. Arborist report: Planning division may require licensed arborist report. Replacement ratio: 1 tree per 200 sq ft of landscaped area. Dead tree deadline: Replace within 60 days of written notice.

Removing, destroying, or topping a protected tree without planning division sign-off violates section 13-108 and is enforceable under the citywide general penalty at section 1-33, which applies regardless of whether the removal was negligent or intentional. Code enforcement can require replacement trees sized to match what was removed, and dead, dying, or diseased trees left unreplaced more than 60 days after written notice from development services or public services add a second violation.

Water Restrictions

Costa Mesa requires an automatic, time-controlled irrigation system for every commercial, industrial or multi-family residential landscape project, engineered so overspray and runoff onto streets and sidewalks are minimized. Any irrigation system serving a project of one acre or more must run on reclaimed water whenever the water agency has it available.

Key details: Auto sprinkler mandate: commercial/industrial + residential >2 units. Reclaimed water mandate: projects 1 acre+, when available. Watering schedule: set by the local water district. Runoff standard: overspray/runoff onto streets, sidewalks minimized. Maintenance duty: owner; CIMIS-based scheduling encouraged.

Failing to install the required automatic irrigation controls, running a one-acre-plus project on potable water when reclaimed water is available, or letting overspray and runoff reach the street or sidewalk are violations enforceable under section 1-33 of the code regardless of whether the property owner intended the water waste, and the development services or public services departments can order the system corrected.

Native Plants

Costa Mesa encourages native and drought-tolerant landscaping through compliance with California's Model Water Efficient Landscape Ordinance (MWELO). Rebates for turf replacement are available through Mesa Water District and Metropolitan Water District programs.

Key details: State Requirement: MWELO for projects 500+ sq ft. Turf Rebates: Mesa Water District programs. HOA Restrictions: Limited by Civil Code §4735. Climate Zone: Mediterranean: native species ideal. Plan Review: Development Services (714) 754-5245.

New projects failing to comply with MWELO requirements may have landscape plans rejected. HOAs unreasonably restricting drought-tolerant plants violate California Civil Code Section 4735.

Costa Mesa is more permissive than most cities when it comes to native plants. That said, there are still limits.

Artificial Turf

Costa Mesa allows artificial turf installation on residential properties as a water-saving landscaping alternative. Turf removal rebate programs may apply to transitioning from natural grass to synthetic turf. HOAs cannot unreasonably restrict artificial turf under California law.

Key details: Permit Required: Generally no for standard installs. HOA Restrictions: Limited by state law. Rebates: Check Mesa Water District. Drainage: Must maintain proper drainage. Development Services: (714) 754-5245.

Artificial turf installations creating drainage problems or violating setback requirements may receive code enforcement notices. HOAs that unreasonably prohibit artificial turf may face legal action under state law.

Rainwater Harvesting

California law encourages rainwater harvesting, and Costa Mesa permits residents to collect and store rainwater for irrigation and non-potable uses without a permit for systems under 5,000 gallons. Rebates may be available through Mesa Water District.

Key details: State Law: AB 1750 Rainwater Capture Act. No Permit Needed: Systems under 5,000 gallons. Use: Irrigation and non-potable only. Mosquito Prevention: Containers must be covered. Rebates: Check Mesa Water District.

Rainwater harvesting is legal and encouraged. However, systems creating mosquito breeding habitat or structural hazards may receive health or code enforcement notices. Large unpermitted systems may need retrofit.

Weed Ordinances

Costa Mesa requires property owners to remove weeds, debris, and overgrown vegetation under property maintenance standards. The city may declare severely neglected properties a public nuisance and perform abatement at the owner's expense.

Key details: Requirement: Remove weeds, debris, overgrowth. Fire Code: Remove ignitable vegetation. Nuisance Declaration: For severe neglect. Abatement: City may perform at owner's cost.

Weed violations result in Code Enforcement notices. Non-compliance may lead to nuisance declaration, city abatement at the owner's expense, and liens on the property for unpaid costs.

Tree Trimming

Costa Mesa maintains city-owned street trees through the Public Works Department. Private trees on residential property are the owner's responsibility. Trees must not obstruct sidewalks, streets, or create hazardous conditions for neighbors.

Key details: City Trees: Maintained by Public Services. Private Trees: Owner's responsibility. Hazardous Trees: Owner must remove. Street Obstruction: Must be cleared by owner.

Unauthorized work on city trees may result in fines and restitution. Private tree failures causing hazards are the owner's liability. Code Enforcement addresses complaints about hazardous private trees.

The Bottom Line

Costa Mesa's landscaping rules rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Costa Mesa is broadly strict or permissive.

This guide is based on Costa Mesa's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.