R1, R2, RD, and RM zoned lots each follow different ADU rules under LAMC Section 12.22 A.33 and California state law. Your zoning code is a starting point — the interaction with state law tells you what you can actually build.
CSLB License #1074505
Itamar Ben Asulin on every zoning review
R1 · R2 · RD · RM
Your zoning designation controls what you can build — but it doesn’t work alone. ADU rights in LA come from two places at once: the LA Municipal Code and California state law.
LAMC Section 12.22 A.33 (the section of the Municipal Code that governs ADU and JADU construction) sets local conditions. California Government Code Section 65852.2 ADU law sets a floor that local codes cannot go below. The result is a layered system — what your lot can build depends on which zoning designation it carries, how many units are already on the property, and which state law provisions override local restrictions that would otherwise apply.
The city cannot deny a code-compliant ADU application based on neighborhood character or zoning preference. ADUs are approved by right — administrative approval without discretionary review or hearings — as long as the project meets objective standards. Even under by-right approval, there are real-world reasons why ADU permits take longer than state law promises. For project logistics, our ADU permit services in LA County cover the full process from zoning review through final inspection. Before any of that, look up your zoning code through the LADBS permit and zoning information portal.
Each LA zoning designation carries a specific set of ADU rights under current law. Here’s the breakdown by lot type — what you can actually build before any design conversation begins.
The most common LA residential zoning. Permits one primary dwelling unit per lot. Under current state + LA law, an R1 lot can legally have one primary + one ADU + one JADU.
A duplex lot. Under AB 2221 (2022 California law expanding ADU rights on multi-family lots), R2 ADU rights extend beyond the two primary units.
RD (Restricted Density) and RM (Residential Multiple) are denser LA designations. ADU rights follow the multi-family framework under AB 2221, not single-family rules.
Three lot types across the county, three different outcomes. Here’s how the rules translate into actual unit counts on actual LA lots.
Homeowner wants a rental unit. Existing detached two-car garage, structurally sound, concrete slab, 9-ft interior clearance. Under R1 rules in LA, the garage qualifies as a detached ADU conversion. Non-habitable conversions are treated separately under state law — no reduction in the homeowner’s one-ADU entitlement. Owner can also build a new detached ADU in remaining backyard space, subject to setbacks.
Current state: 2 units (the duplex). Under AB 2221, the owner can add 2 new detached ADUs + convert the existing detached garage into an additional ADU. By-right approval through LADBS — objective code compliance, not neighborhood fit. The Echo Park VHFHSZ location adds an LAFD plan check step but doesn’t change the unit count entitlement.
Owner wants to maximize the property. Under AB 2221’s multi-family conversion formula, 25% of 12 units = 3 non-habitable conversions allowed. 2 new detached ADUs are also permitted. The 1965 construction date means existing units are RSO-covered, but the 5 new ADUs are NOT — that distinction changes the financial model of the asset entirely.
I’m Itamar Ben Asulin, owner of IBA Builders. I’ve been managing ADU projects across LA County since 2015 under CSLB License #1074505 — on R1 lots in Reseda, R2 duplexes in Silver Lake, and RM parcels in Koreatown and Mid-City.
The most consistent issue I see isn’t a construction problem — it’s a zoning assumption. Homeowners read that they can build an ADU, assume the general rule applies directly to their lot, and spend money on plans before anyone has confirmed what their specific zoning designation and lot configuration actually allow.
What general online articles miss: the city’s zoning maps show the designation. California law states broad rights. But the combination of your specific designation, your current unit count, your lot’s recorded dimensions, any covenant or deed restriction on file with the county, and whether your neighborhood falls within the Coastal Zone or a fire hazard severity zone — that combination determines what you can actually build. And that combination is specific to your parcel, not your neighborhood. This is also where hillside lot zoning and structural constraints in LA add another layer — slope conditions and access requirements can affect what a code-compliant design actually looks like on the ground.
At IBA, we pull the lot data before we quote. We check LAMC Section 12.22 A.33, the state ADU law, and any overlay conditions that apply to your address before any design conversation begins. That review takes time. It’s the only way to give you an accurate answer about what your lot can support.
A zoning review makes sense the moment you’re seriously considering an ADU. You don’t need a finalized plan. You don’t need a budget. You need an address and a clear goal — IBA handles the rest. Pulling plans and paying a designer before the zoning analysis is complete can cost real money when the lot supports something different from what the design assumed. Starting with the zoning review protects that investment.
IBA Builders holds CSLB License #1074505. We’ve been navigating the LADBS ADU permit process as part of the full project workflow across LA County since 2015. That review is how every project starts — it costs you a conversation, not a retainer. Once the zoning picture is clear, the next practical question is what an ADU costs once you know what your lot allows, and that answer changes meaningfully depending on whether you’re converting an existing structure or building new.
Under current California and LA law, an R1 lot can legally have three units: one primary dwelling (the existing home), one ADU of up to 1,200 sq ft (or 50% of the primary’s floor area, whichever is less), and one JADU of up to 500 sq ft within the existing structure. The ADU can be detached (built in the backyard) or attached. The JADU must share an entrance with the main dwelling and the owner must occupy either the primary home or the JADU.
AB 2221 (effective 2022) clarified and expanded ADU rights on multi-family zoned lots. On an R2 lot, owners can add two new detached ADUs IN ADDITION to the two existing primary units, plus convert non-habitable space (like a garage) into an additional ADU. That’s potentially five units on a lot zoned for two. On RD/RM lots, owners can add up to two detached ADUs regardless of existing unit count, plus convert non-habitable space at a ratio of up to 25% of the existing unit count. The owner-occupancy requirement does not apply to R2 or multi-family lots.
The conversion ratio applies to the existing unit count. An RM lot with 12 existing apartments can convert up to 3 non-habitable spaces (laundry rooms, storage units, parking structures) into ADUs. A 20-unit RM lot can convert up to 5. These conversions are in addition to the 2 new detached ADUs allowed. The math compounds: a 12-unit lot could potentially have 17 total units (12 + 2 + 3), and a 20-unit lot could have 27. The 25% rule rounds down to the nearest whole unit.
FAR (floor area ratio) is the ratio that limits total building floor area relative to lot size. California Government Code Section 65852.2 exempts ADUs of 800 sq ft or less from local FAR restrictions — meaning the city cannot use FAR limits to block a code-compliant ADU at or below that size. ADUs larger than 800 sq ft may still be subject to local FAR calculations, and that calculation varies by lot and block. If you’re targeting maximum unit size, the 800 sq ft threshold is a meaningful design decision point.
Depends on lot type and ADU type. On an R1 lot, owner-occupancy of either the primary home or the JADU is required if you build a JADU. The standard ADU on an R1 lot does NOT require owner-occupancy. On R2 lots, the owner-occupancy requirement does not apply — an investor who owns a duplex can add ADUs without living on-site. Same applies to RD/RM multi-family properties. This is a major change from pre-2020 LA rules and matters significantly for investment property planning.
Start with a zoning review — IBA does this before any design work begins. If you know your zoning designation, we can confirm your ADU rights and lot-specific eligibility in a single conversation. If you don’t know your designation, we can look it up with your address. No plans required. No commitment required. Just an address and a goal — we’ll confirm exactly what current LA ADU zoning law allows you to build.