ADUs & Additions in Whittier

City of Whittier Community Development Department, Building & Safety Division. Projects are first evaluated by the Planning Services Division, then go through plan review and permit issuance with the Building & Safety Division, both part of the Community Development Department. In the H-R Hillside Residential zone no building permit is issued until a hillside development plan is approved, and later buildings and structures must be found consistent with that approved plan. In the Hadley-Greenleaf, Central Park, College Hills and Earlham historic districts, alterations, additions and new improvements need a Certificate of Appropriateness, or a waiver, before a permit is issued. Additions or accessory structures under 500 square feet and ADUs of 800 square feet or less that are not visible from a public right-of-way can qualify for the waiver when they follow the preservation and design guidelines. We prepare the drawings, make the submittal and handle plan-check corrections ourselves, so you are not the one chasing plan check.

Hillside parcels in the H-R zone take their lot area, building site and building heights from each approved hillside development plan. Elsewhere, new R-1 lots generally must be at least 7,000 square feet and new R-E estate lots at least 15,000, buildings including accessory buildings may cover no more than 40 percent of the lot in either zone, and heights top out at 35 feet in R-1 and 30 feet in R-E. Where an R-1 neighborhood is predominantly single story, the city may limit or prohibit second-story additions. One local condition that shapes the work: In the H-R Hillside Residential zone, cuts and fills may not exceed 20 feet in height or a 2:1 slope, ground of 50 percent slope or steeper cannot be graded except to correct earlier grading, landslides or unstable soil, and each building and structure must fit the natural landform as closely as possible.

All of it, including Uptown Whittier, Hadley-Greenleaf, Central Park and College Hills. Our crews run every job out of our Cahuenga Pass base in Los Angeles, with our own people on site.

Detached ADU: generally $150,000 to $400,000+ across Southern California. What moves it is square footage, finish level, utility runs, and site access; garage conversions typically run well below a ground-up detached build. We give line-item pricing after seeing the site rather than quoting a number over the phone.

Plan a realistic year. Design and engineering typically take one to three months, city plan check and corrections add several more, and construction usually runs four to eight months depending on size and site access.

Usually yes, and often substantially, because the foundation, walls and roof already exist. The trade-offs are that you lose the garage, and older slabs and framing sometimes need upgrading to meet current code.

California ADU law is designed to allow long-term rental, and an ADU is one of the few ways to add rentable square footage to a single-family lot. Short-term rental rules vary by city, so confirm your local ordinance before counting on that income.

Yes. Plans, engineering, Title 24 and the city submittal are all handled in-house, including responding to plan-check corrections. That is a service we sell on its own, so it is not something we hand off.