Orange County
Building Design and Permit Plans in Costa Mesa
Costa Mesa is three approvals, not one. The City reviews the plans, the Costa Mesa Sanitary District issues the sewer permit, and Mesa Water reviews service where it applies; each has its own redlines and its own fee, and a signed sewer permit and approved sewer plans have to be on site when work starts. Our Costa Mesa work is ADUs, additions and remodels on record since 2021.
Our Work in Costa Mesa
An addition reached approved sewer plans in August 2025, with the Sanitary District requiring the signed sewer permit and plans on site and any revision reported; the building side was coordinated with the City and the water district. A garage conversion with an addition and remodel is in plan check as of April 2026, with a soils report required and first-round corrections in hand. A 2024 project showed that the school-fee hold is informational and does not stop review, while the sewer permit runs separately. On a demolition and remodel, the City held that demolition-only plans must not reference new construction, so we separated the scopes and the plans were approved in 2024. A 2022 ADU with an addition drew water plan-check redlines that had to be answered, with fees confirmed, before review continued.
How review works in Costa Mesa
City planning and building review is separate from the Costa Mesa Sanitary District sewer permit and Mesa Water review.
What comes up most: three approvals to gather, and demolition applications kept to demolition.
Our Services in Costa Mesa
ADU Design
Detached ADUs, garage conversions, junior ADUs, and two-story units. Permit-ready plans prepared for Costa Mesa’s specific requirements.
Custom Home Design
Ground-up residential design from modern to traditional. Complete plan sets prepared for permitting.
Additions & Remodels
Room additions, second stories, kitchen and bath redesigns, whole-home renovations. Seamless integration with existing structures.
Plan Check Corrections
Plans stuck in review? We take over stalled projects, resolve code issues, and get permits approved.
Legalize Unpermitted Work
As-built documentation, code compliance analysis, and permit legalization for existing unpermitted additions and conversions.
Duplexes, Triplexes & Fourplexes
Duplexes, triplexes, and fourplexes, up to four units and two stories. Density analysis and code-compliant design.
Start Your Costa Mesa Project
Free consultation. We’ll review your project and the permit path, then quote a flat fee in writing. No pressure, no obligation.
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Service Area
Los Angeles County and Orange County
Pasadena · Arcadia · Glendale · Long Beach · and 80+ more cities
Availability
Mon – Fri, 9am – 6pm
Weekends by appointment