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Environmental Rules

Costa Mesa's Environmental Rules: The Rules That Matter

By CityRuleLookup Editorial Team

Every city handles environmental rules a little differently. In Costa Mesa, California, there are 5 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.

Stormwater Management

Costa Mesa regulates stormwater runoff as a co-permittee under the Orange County NPDES MS4 Permit issued by the Santa Ana Regional Water Quality Control Board. New development and significant redevelopment must incorporate best management practices and Low Impact Development strategies to prevent polluted runoff from reaching storm drains and waterways.

Key details: Governing Code: CMMC Title 14 - Water Quality. Regional Permit: OC NPDES MS4 Permit. SWPPP Required: Sites disturbing 1+ acre. LID Required: New development/redevelopment. Public Works: (714) 754-5343.

Illicit discharge violations are enforced by Costa Mesa Code Enforcement and Public Works. Violations of the Municipal Code can result in administrative citations and fines. State NPDES violations may carry penalties up to $10,000 per day. Contact Public Works at (714) 754-5343.

Erosion Control

Costa Mesa requires erosion and sediment control measures for all construction and grading activities. The city has adopted Article 8 of Title 7 of the Orange County Codified Ordinances (Grading Manual) with local modifications, requiring developers to prevent soil erosion and sedimentation during and after construction.

Key details: Grading Code: OC Article 8, Title 7 (adopted). SWPPP Threshold: 1+ acre disturbance. Fill Exemption: <1 ft deep, <50 cu yd, <5:1 slope. Planter Exemption: <3 ft deep, <50 cu yd. Contact: Development Services (714) 754-5245.

Failure to implement required erosion controls can result in stop-work orders, administrative citations, and fines from Costa Mesa Code Enforcement. State NPDES violations for sediment discharge carry penalties up to $10,000 per day. Contact Development Services at (714) 754-5245.

Coastal Development

Portions of Costa Mesa fall within the California Coastal Zone. Because Costa Mesa does not have a certified Local Coastal Program (LCP), the California Coastal Commission retains permit authority over development in the coastal zone, requiring Coastal Development Permits for most construction and development activities in those areas.

Key details: Coastal Zone: Portions of Costa Mesa included. LCP Status: Not certified by CCC. Permit Authority: California Coastal Commission. Processing Time: 3-6 months typical. CCC South Coast: (562) 590-5071.

Development in the coastal zone without a required Coastal Development Permit is a violation of the California Coastal Act. The Coastal Commission can issue cease-and-desist orders, restoration orders, and civil penalties up to $15,000 per day of violation. Contact the South Coast District Office at (562) 590-5071.

This is one of the stricter rules in Costa Mesa's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

Grading & Drainage

Costa Mesa requires grading permits for most earth-moving activities and enforces drainage standards to prevent water from flowing onto neighboring properties. The city has adopted the Orange County Grading Manual with local modifications governing excavation, fill, and drainage requirements.

Key details: Grading Code: OC Article 8, Title 7 (adopted). Permit Required: Most grading/excavation/fill. Fill Exemption: <1 ft, <50 cu yd, <5:1 slope. Plans By: Licensed civil engineer. Contact: Development Services (714) 754-5245.

Grading without a permit can result in stop-work orders, double permit fees, and administrative citations. Altering drainage to affect neighboring properties may result in code enforcement action and civil liability. Contact Development Services at (714) 754-5245.

Flood Zones

Costa Mesa participates in the National Flood Insurance Program (NFIP) and regulates floodplain development under Title 13 (Planning, Zoning and Development), Chapter V, Article 8 of the Costa Mesa Municipal Code. Sections 13-81 through 13-83 govern uses permitted in designated floodway fringe and Special Flood Hazard Areas (SFHAs) shown on FEMA Flood Insurance Rate Maps, development standards for floodway areas, and exceptions. The Santa Ana River forms Costa Mesa's western boundary and Upper Newport Bay borders the city's eastern edge - both are primary regulated drainages. State authority for floodplain regulation derives from California Water Code Sections 9100 et seq. (Flood Control) and Section 8400 (state floodway designation). FEMA's currently effective Orange County FIRM panels apply to all floodplain determinations within city limits.

Key details: Local Code: Costa Mesa MC Title 13, Chapter V, Article 8 (Sections 13-81 to 13-83). State Law: Cal. Water Code Sections 9100, 9620, 9650. Federal Law: 44 CFR Parts 59-72 (NFIP). Primary Drainages: Santa Ana River (west), Upper Newport Bay (east). Flood Maps: FEMA Orange County FIRM (msc.fema.gov).

Unpermitted development, fill, or substantial improvement within a designated floodway or SFHA violates Costa Mesa Municipal Code Title 13, Chapter V, Article 8 and is enforceable under the city's general code-enforcement provisions, including stop-work orders, administrative citations, and abatement orders. Building below the regulatory flood elevation, encroaching in the floodway, or misrepresenting elevation data on permit applications can trigger denial of building permits and revocation of certificates of occupancy. Sustained noncompliance jeopardizes the city's NFIP standing under 44 CFR Part 59 and can lead to community probation or suspension - which would terminate residents' eligibility to purchase federally backed flood insurance. State-designated floodway encroachments without a Central Valley Flood Protection Board or successor encroachment permit (Cal. Water Code Section 9650) are independently actionable.

This is one of the stricter rules in Costa Mesa's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

The Bottom Line

Costa Mesa is tougher than many cities when it comes to environmental rules. Out of the 5 rules covered here, 2 are rated strict. If you are a homeowner, renter, or business owner in Costa Mesa, take the time to understand these requirements before they become a problem. Most violations come with fines, and some repeat violations can escalate.

Keep in mind that Costa Mesa can amend these rules at any council meeting. For the most current version of any rule mentioned here, check the specific ordinance page, where we track updates as they happen.