Building an ADU in Beverly Hills. Rules, costs, timeline.

Bigger than almost anywhere else in Los Angeles County, and it depends on where in the city you are. In the Central Area north of Santa Monica Boulevard and in the Hillside Area, an attached or detached ADU may reach 1,400 square feet. In the Central Area south of Santa Monica Boulevard the cap is 1,200 square feet. In Trousdale Estates it is 850 square feet for a studio or one-bedroom and 1,000 square feet with more bedrooms. In every case the site's remaining allowable floor area applies as a second limit — no floor-area, open-space, coverage or front-setback rule may reduce an ADU below 800 square feet (BHMC § 10-3-5000.A.4.b).

Work through it in this order, because the labels are defined by geography rather than by zoning district. If your property is north of Doheny Road and east of Schuyler Road, you are in Trousdale Estates — excluding land zoned R-1.X and the Greystone Mansion property. Otherwise, if you are north of Sunset Boulevard, you are in the Hillside Area. Everything else is the Central Area, which then splits north and south of Santa Monica Boulevard for size and height purposes. "Central north" and "Central south" are not zones; they are that split. Confirm with the City's zoning map or by calling a planner before you design anything.

Up to 22 feet in the Central Area south of Santa Monica Boulevard, and up to 25 feet north of it (BHMC § 10-3-5000.A.6.a). In the Hillside Area and Trousdale Estates the code incorporates Gov. Code § 66321(b)(4) by reference, which the City renders as 16 feet, rising to 18 feet within a half-mile walking distance of a major transit stop, plus up to two more feet to align the ADU roof pitch with the main house. There is also a provision most people miss: on a Central Area estate lot of at least 24,000 square feet, a detached ADU within the principal building area may go two stories at the primary dwelling's own height limit.

Three under Gov. Code § 66323(a), a fourth on HCD's reading of § 66314, and a fifth on a large lot here. Section 66323(a) requires the City to allow a conversion ADU, a Junior ADU and a newly built detached ADU of up to 800 square feet in combination — HCD's March 2026 Handbook states that local agencies "must allow at least one ADU constructed from existing space, one JADU, and one newly constructed detached ADU," and the City's own ADU Development Guides agree, listing "Maximum 3 Units." The Handbook then adds at p. 18 that "in addition to the units described in Government Code section 66323, a local agency must allow at least one unit described in Section 66314" — in Beverly Hills that is the ordinance ADU, the one that reaches 1,400 square feet. On a lot of 13,000 square feet or more the incentive ADU sits on top of all of it. The codified text at BHMC § 10-3-5000.A.1 reads more narrowly than any of this, which is one of the things the pending amendment is expected to fix; the § 66314 point is HCD guidance rather than express statutory text, so put it in writing at pre-application.

It is a bonus unit unique to Beverly Hills, granted in exchange for a rental commitment. On a single-family lot of 13,000 square feet or more, BHMC § 10-3-5000.A.1.a allows one additional ADU — attached or detached new construction, up to 800 square feet, with four-foot side and rear setbacks. The trade is that it must be rented, with the initial and each subsequent term at least one year, with no subletting and no short-term use. One detail makes it unusually valuable: an ordinary ADU is capped at the lesser of its area maximum and your remaining allowable floor area, while the incentive ADU's 800 square feet is stated flat in the City's guide with no such limiter. It also cannot be a Junior ADU or a conversion, so it is genuinely an extra unit. One limitation: an incentive ADU must meet every objective standard and cannot request deviations through a minor accommodation permit.

State law allows considerably more than the local code says. BHMC § 10-3-5001 states that "no more than two detached accessory dwelling units are allowed on a lot that has an existing or proposed multi-family dwelling." Gov. Code § 66323(a)(4)(A)(ii) requires ministerial approval of up to eight detached ADUs on a lot with an existing multifamily dwelling, capped at the number of units already there. Separately you may convert non-livable space at one unit or 25 percent of your existing units, whichever is more. The City's Planning Commission recommended raising the local cap from two to eight in June 2026, which is a fair indication of where this lands.

Four feet from side and rear lot lines is the most the City may require. Where the ADU abuts an alley, no setback is required at all. On the Central Area flats, with their extensive alley grid, that is a significant unlock. In the Hillside Area and Trousdale Estates the primary dwelling's setbacks apply, but capped at four feet. A conversion or a rebuild within an existing footprint inherits the existing setbacks with nothing added (BHMC § 10-3-5000.A.9.c). One thing to watch in the Hillside Area: the City's own development guide sets a 100-foot minimum front setback for a detached ADU. It cannot be applied to stop you building. Gov. Code § 66321(b)(3) bars any front setback that does not permit an ADU of at least 800 square feet with four-foot side and rear setbacks, and HCD says front setbacks "cannot preclude an ADU of at least 800 square feet from being built on the property, even if that ADU would exist partially or wholly within the front setback." For a § 66323 unit it is stronger still — HCD says the City cannot impose local siting standards on those at all. On a shallow hillside lot that is the whole ballgame; raise it in writing at pre-application.

One space is the default, and the state exemptions at Gov. Code § 66322(a) remove it in six situations — most Beverly Hills lots meet at least one. No parking is required where the ADU is within a half-mile of transit, in a historic district, part of the existing primary or accessory structure, in an on-street permit area where the occupant is not offered a permit, within one block of a car share, or submitted alongside a permit for a new dwelling. Junior ADUs need no parking at all under Gov. Code § 66334(a). And replacement parking is never required when a garage is converted or demolished (Gov. Code § 66314(d)(11)).

No. Owner-occupancy may not be required for an ADU under Gov. Code § 66315. Junior ADUs are different, but the rule narrowed on January 1, 2026: under Gov. Code § 66333(b) as amended by AB 1154, owner-occupancy applies only where the Junior ADU shares sanitation facilities with the main house. Give it its own bathroom and the requirement does not apply. A deed restriction is still recorded under § 66333(c) covering separate sale and unit size, and the City charges a covenant processing fee for it. On a standard ADU, note that HCD says a local agency cannot impose a deed restriction at all — ask for any covenant requirement in writing and cite Gov. Code § 66315. Separately on tenancy: you cannot let an ADU short-term. Gov. Code § 66323(e) requires a rental term longer than 30 days for these units, and an incentive ADU is stricter still — BHMC § 10-3-5000.A.7.b requires each term to be at least one consecutive year, with no subletting.

The building permit and plan check are valuation-based, so the figure depends on your project. Around them sit some published line items worth knowing. A $463 certificate of occupancy for the ADU. A $95 permit issuance fee. Plan review at $318 an hour. And covenant processing at roughly $1,034 to $1,467, plus City Attorney costs. Electrical and plumbing are each charged at 8.33 percent of the building permit fee — not of project valuation, which is a common misreading — energy permit at 20 percent of the building permit fee, and a 3.7 percent surcharge applies to all development permits and planning applications. No impact fees or park fees may be charged on an ADU of 750 square feet or less, and BHMC § 10-3-5000.A.16 says so in the local code as well as the statute.

You leave the ministerial track, and it gets expensive. A code-compliant ADU is reviewed ministerially through building permit plan check — no hearing, no discretionary review. If you want to exceed the standards on height or floor area, the route is a minor accommodation permit under BHMC § 10-3-3600.U at $8,128 at staff level or $22,153 at commission level, and depending on the configuration an R-1 permit may be needed too. In the Hillside Area an R-1 single-family review runs $23,832. Those numbers are the reason staying inside the objective standards is usually the whole game here.

Yes. The City runs a Preapproved ADU Program with seven approved designs currently listed, including plans from Lauri Morrison Studio, Inchoate Architecture, nonzero\architecture and YD Group, ranging from a 438 square foot one-bedroom upward. The plans are described as roughly 70 percent complete for permitting: you contract directly with the designer, then apply for a building permit and add your property-specific details. Prices are set by the designers and are not published by the City. Every California city has been required to run a pre-approval program since January 1, 2025 under AB 1332.

A pool house or other enclosed accessory structure, usually yes — a conversion may add up to 150 square feet beyond the existing dimensions for ingress and egress. An unenclosed structure, no. BHMC § 10-3-5000.A.4.c specifically excludes conversion of "unenclosed accessory buildings or unenclosed accessory structures, such as patios, gazebos, breezeways, carports, porte cocheres, or similar structures." Those may still be replaced with new construction, but the project is then measured as a new detached ADU rather than a conversion. Porte cocheres are common on these properties, so it is worth checking early.

A few, and one catches people. New or relocated windows within 10 feet of a side or rear property line must either sit at least six feet above finished grade, or be awning-style windows opening no more than six inches and fitted with translucent glass. Newly constructed ADUs must also stand at least six feet from any other building on the site, which on a dense lot with an existing pool house or cabana often drives the site plan more than the setbacks do. If the property is a listed historic resource, the Secretary of the Interior's Standards apply to the design.

Often yes, and it is worth checking on an older property. Gov. Code § 66311.7 bars the City from denying a permit for an unpermitted ADU or Junior ADU built before January 1, 2020 on the grounds that it violates building standards or does not comply with ADU law, and § 66311.7(e) bars impact fees and connection or capacity charges on the legalized unit except where utility infrastructure has to be corrected for health and safety. The section also bars the City from penalizing you for having had the unit. Those protections fall away where the City finds that correcting the violation is necessary to protect health and safety, or where the building is deemed substandard under Health and Safety Code § 17920.3. On a city of pre-1970 properties with converted pool houses, maid's quarters and garages, this is worth raising before you assume an old unit has to come out.