Program · Apartment owners

Up to 8 new homes behind your building

Since January 2025, California lets an existing apartment property add detached ADUs, one for every existing unit up to eight, plus conversions of garages and storage. No rezoning, no replacement parking, and often no new parking.

Does my property qualify?

Up to 8

detached ADUs, never more than existing units

25%

of units again as conversions, at least 1

replacement parking spaces

60 days

for the city to act on a complete application

Who qualifies

You're likely a fit if

The lot has a building with two or more attached units (duplex, triplex, fourplex or larger)
It's in a zone that allows multifamily housing
There is room behind or beside the building, or a garage or storage to convert
You want rental income without buying another property

On the lot

What it looks like

The orange piece is what gets built.

Real project · Maywood

Eight more homes, found on an existing lot

A 1960s apartment building, its old carports, and the law that turned them into ADUs.

homes before

new ADUs

homes in all

See the case study Check my building

The numbers

What your building can add

Detached ADUs are capped at the number of existing units and at 8. Conversions of non-living space add at least 1, or 25% of the units.

SB 1211, by building size

Existing units	Detached ADUs	Conversion ADUs	Up to
2 (duplex)	2	1	3 new homes
3	3	1	4 new homes
4 (fourplex)	4	1	5 new homes
8	8	2	10 new homes
20	8	5	13 new homes

How we do it

How it runs

Free Lot Check

How many units are allowed and where they fit. Free.

Site plan

Placement around parking, utilities and fire access.

Design and permit

Usually 4 to 8 months together, depending on the city.

Build

Built together so the tenants see one project, not five.

Questions

What owners ask

Do I lose parking?

A space removed to build an ADU doesn't have to be replaced under SB 1211.

Can my tenants stay during construction?

Usually yes. We phase the work around access and utilities.

What does it cost per unit?

It depends on size and site. Building several at once lowers the cost per door. After the Lot Check and design you get a written quote.

What about rent control?

New ADUs are generally free of local rent caps, and exempt from the state cap for 15 years. Eviction protections can still apply, and rules differ by city. We flag it in the Lot Check.

Sources

Where this comes from

Checked October 2026. Laws change; we re-check every project against the current code before design. General information, not legal, tax or financial advice.