Two houses face each other across a quiet street in the hills. One goes up three stories with a flat roof; the other is told 28 feet and no more. Nobody has pulled a favor — the two lots simply carry different letters and numbers, and in the Los Angeles estate zones those numbers do a great deal of work.
RE is the city's Residential Estate Zone, and it exists in five variants: RE9, RE11, RE15, RE20 and RE40. All five permit one-family dwellings and share the same use list. What changes between them is the geometry — side yards run from 5 feet to 10 feet, and the height limit is 33 feet in RE9 against 36 feet in the four larger variants, each dropping by several feet on a low-sloped roof (§ 12.07.01, § 12.21.1).
Key numbers
| Variant | Side yard, main building up to two stories | Height limit (outside hillside and coastal areas) |
|---|---|---|
| RE9 | 5 ft; 7 ft outside hillside/coastal areas | 33 ft, or 28 ft with a low-sloped roof |
| RE11 | 5 ft; 7 ft outside hillside/coastal areas | 36 ft, or 30 ft with a low-sloped roof |
| RE15 | 10% of lot width, minimum 5 ft, maximum 10 ft | 36 ft, or 30 ft with a low-sloped roof |
| RE20 | 10 ft | 36 ft, or 30 ft with a low-sloped roof |
| RE40 | 10 ft | 36 ft, or 30 ft with a low-sloped roof |
Side yards from § 12.07.01; heights from § 12.21.1. "Low-sloped" means the roof of the uppermost story has a slope of less than 25 percent.
| Other RE standards | Requirement |
|---|---|
| Front yard | 20% of lot depth, need not exceed 25 ft (§ 12.07.01) |
| Front yard on a developed block | Average of prevailing front yards, never more than 40 ft (§ 12.07.01) |
| Lot size to keep horses | 17,500 sq ft, one per 4,000 sq ft (§ 12.07.01) |
| Lot size for a private stable | 20,000 sq ft, one equine per 5,000 sq ft (§ 12.07.01) |
| Lot size for accessory living quarters | 20,000 sq ft (§ 12.07.01) |
| Coastal Zone height, Height District No. 1 | 45 ft (§ 12.21.1) |
Height is a two-part answer, and the roof is the second part
Most people look up one number. The code gives you two, and which one applies depends on the pitch of your roof.
In the RE11, RE15, RE20, RE 40 or RA Zones, no Building or Structure shall exceed 36 feet in height.
Immediately after that sentence comes the exception that catches modern designs: where the roof of the uppermost story, or of a portion of the building, has a slope of less than 25 percent, the maximum drops to 30 feet. The same structure applies one rung down — RE9 sits with R1 and RS at 33 feet, falling to 28 feet on a low-sloped roof.
That is a six-foot penalty for a flat roof, and it is the single most common surprise in an estate-zone remodel. A pitched design and a flat design of the same interior volume are not treated the same.
Two other height rules can override all of it. Inside the Coastal Zone in Height District No. 1, the RA, RE, RS, R1 and R2 zones are all capped at 45 feet. Inside a hillside area, the limits come from a separate hillside provision, not from these figures. And where existing one-family dwellings on 40 percent or more of both sides of the block already exceed the limits, the block's maximum may become the average height of those taller houses.
Side yards climb with the lot size
RE side yards are the clearest illustration of the variants doing real work.
RE9 and RE11 start at 5 feet each side, dropping to 10 percent of lot width with a 3-foot minimum on lots narrower than 50 feet. But outside hillside areas and the Coastal Zone, that same pair is held to 7 feet each side, relaxing to 10 percent of width — again with a 3-foot floor — only on lots narrower than 70 feet.
RE15 uses a proportion instead: 10 percent of the lot width, never less than 5 feet, and never required to exceed 10 feet.
RE20 and RE40 are the simplest: 10 feet on each side of a main building, flat.
Above two stories, add one foot to each required side yard per additional story. In place of that, new construction or a ground-floor addition on an RE9, RE11, RE15 or RE20 lot outside hillside and coastal areas may instead add one foot for each ten-foot increment, or fraction of one, above the first 18 feet of building height.
What you may put on an estate lot
The use list is a one-family list with a rural streak:
- One-family dwellings, and government-owned parks, playgrounds or community centers.
- Truck gardening and the keeping of equines, poultry, rabbits and chinchillas, in conjunction with the residential use and never for commercial purposes. Horses need 17,500 square feet and are limited to one per 4,000 square feet.
- Accessory buildings — private garages, accessory living quarters, servant's quarters, recreation rooms and private stables. Accessory living or servant's quarters require 20,000 square feet; a stable requires 20,000 square feet and one equine per 5,000 square feet. Any combination of these may share one building of no more than two stories.
- Two-family dwellings where the lot has a side lot adjoining a commercial or industrial zone and does not extend more than 85 feet from that boundary.
- Backyard beekeeping as an accessory use, plus home occupations, name plates and signs.
Note the internal split on horses: you may keep equines from 17,500 square feet, but the stable to house them is an accessory building with its own 20,000 square foot threshold. Those are two different tests in the same section.
As in the other residential zones, lots mapped as Public, Quasi-Public, Open Space, waterway or freeway right-of-way — and annexed land with no plan amendment — need prior approval even for permitted uses, and anything off the list runs through the conditional use process (§ 12.24).
The front yard is deeper than in the standard house zone
RE uses the same percentage as the One-Family Zone — 20 percent of the lot depth — but caps it at 25 feet rather than 20. The prevailing-setback averaging works identically: where developed lots whose front yards vary by no more than ten feet make up 40 percent or more of the frontage, the required front yard becomes their average, and nothing can push it past 40 feet. On key lots, the averaging applies for up to 85 feet from the rear lot line of the reversed corner lot.
What the source sections do not cover
One important gap: the minimum lot area for each RE variant is set in the lot-area subdivision of the same section, which is not reproduced in the text quoted here — so do not infer a lot size from the number in the zone name based on this page. The rear yard requirement is in that same unquoted part.
On floor area, the general height section's limit of three times the buildable area expressly excludes the RA, RE, RS and R1 zones, so a residential estate lot's floor area is governed elsewhere (§ 12.21.1). Parking, hillside grading rules, specific plans and Historic Preservation Overlay Zones are further layers, and side yard and height requirements in a specific plan, an overlay zone or a subdivision approval take precedence over the zone's own numbers.
Confirm your parcel's exact variant and its overlays before designing to any figure here. Our Los Angeles code overview covers the surrounding local rules.
