How LA County defines like-for-like
The county's Zoning Code treats a like-for-like replacement as a structure of the same size, in the same location and for the same use as the legally established structure that burned. Within that, you have real freedom: the county states that the new house can be smaller than the old one or have a different interior floor plan. Only Regional Planning decides whether a project qualifies.
The prior square footage is not simply what you remember. The county reviews permit records, prior zoning approvals, Assessor data and photographs to establish what was on the lot, and it typically does not keep residential plans on file. Rooms that were added without permits may not count, so we gather these records first and compare them before anyone designs to a number.
The Eaton Fire allowance: 10 percent or 200 square feet
In the Eaton Fire area, a like-for-like house may exceed the prior footprint and gross floor area by 10 percent or 200 square feet, whichever is greater. The Palisades Fire area only gets the 10 percent figure, so Altadena's rule is more generous for smaller homes. On a 1,400 square foot house, 10 percent is 140, so the 200 square foot figure applies and the rebuild can reach about 1,600 square feet. On a 2,800 square foot house, 10 percent is 280 square feet, which is the larger number.
The interim ordinance adds several related standards. Height may match the prior structure or the zoning limit, whichever is greater, as long as the number of stories does not increase. The house can shift on the lot if it keeps at least 50 percent of its original footprint. In the R-1 zone the minimum front setback is 20 feet: a home that sat farther back may move forward to 20 feet, and a home that sat closer than 20 feet may keep its old setback or move back. A January 2026 interpretation applies the same flexibility in Altadena's three legacy front yard Setback Districts, except where recorded, unexpired CC&Rs require more.
Current codes still apply to every rebuild
Like-for-like status waives current zoning standards such as today's setbacks, and a legally established nonconforming setback can be kept. It does not waive the current Building, Fire, and Health and Safety codes. New homes need fire sprinklers, must be solar-ready and electric-ready, and on lots in a fire hazard severity zone they need fire-resistant construction and a fuel modification plan.
For like-for-like single-family and duplex rebuilds in the Eaton Fire area, the county has suspended four requirements: electric vehicle-ready infrastructure, the cool roof requirement, graywater-ready plumbing, and low impact development rules for buildings built before 2009. Parking for the rebuild may also be uncovered, although the number of required spaces does not change. On a septic system, the county's fact sheet says a like-for-like home must keep the same number of bedrooms and other rooms of 70 square feet or more.
What turns a rebuild into a non-like-for-like project
A project leaves the like-for-like lane if it grows beyond the 10 percent or 200 square foot allowance, adds a story, relocates while keeping less than half of the old footprint, or changes the use. On septic, adding bedrooms or flow also triggers a system upgrade. If your plans do not qualify, the county says staff will tell you which process applies and you can redesign to like-for-like before spending more.
Non-like-for-like rebuilds follow current zoning, and the county notes some cases may need discretionary review with a public hearing. The interim ordinance created a streamlined option for certain modifications to Altadena CSD and other development standards: the Director of Regional Planning decides as Zoning Administrator without a hearing, after mailing notice to adjoining owners and allowing at least 15 days for comment, and the decision can be appealed.
Altadena CSD standards for a larger or redesigned home
The county's August 2025 handout for non-like-for-like rebuilds summarizes the Altadena CSD standards for R-1 lots. Side yards are 10 percent of the average lot width, never less than 5 feet. Rear yards are 25 feet on lots under 20,000 square feet and 35 feet on larger lots. Height is limited to 30 feet on lots under 20,000 square feet and 35 feet at or above that size, no part of a building within 15 feet of a property line may exceed 23 feet, and homes are capped at two stories above grade, with a basement counted as a story.
Size is controlled by gross structural area and lot coverage, each capped at one quarter of the net lot area plus 1,000 square feet and never more than 9,000 square feet. On a 10,000 square foot lot, that works out to 3,500 square feet. Oak trees matter too: a rebuild of either type avoids an Oak Tree Permit if it affects a protected oak no more than the old structure did. We run these numbers for your lot early, because they decide whether a bigger home is realistic.
Choosing a path for your lot
Like-for-like is usually the more predictable route through zoning, and it can carry a new ADU or junior ADU as long as those units meet current rules. A redesign can make sense when the old house never worked well or the lot supports noticeably more space under the CSD. We lay out both options with the square footage, setbacks and review steps each one involves, then give you a written scope and price for the one you choose. Rules have shifted more than once since 2025, so we confirm the current standards with Regional Planning before design is final.