Because of the critical need for affordable housing in California, new state laws encourage ADUs. With lower building permit costs and required faster permit approval time of 60 days, homeowners can build a rental unit or additional space for an adult child, a quiet home office, or a guest house.
Recent California bills make California ADUs easy to build because many of the old restrictions that cities placed on ADUs is now obsolete. ADUs may be built concurrently with a single-family dwelling. Areas where ADUs can be built include all zoning districts that allow single-family and multifamily residences. Building fees from utilities such as special districts and water corporations have been limited with exemptions or reductions in impact
Responding to the critical need for affordable housing in California, new state laws encourage ADUs. With lower building permit costs and required faster permit approval time of 60 days, homeowners can build a rental unit or additional space for an adult child, a quiet home office, or a guest house.
Recent California bills make California ADUs easy to build. Many of the old restrictions that cities placed on ADUs are now obsolete. The new laws permit ADUs in all zoning districts for single-family and multifamily residences. Property owners may build up to two ADUs concurrently with a single-family dwelling. Limits on building fees from utilities such as special districts and water corporations include exemptions or reductions in impact fees.
Housing experts point out adding more houses in existing residential neighborhoods without changing their character the same way apartment buildings do.
California state law AB-68 and AB-881 ADU Building Requirements:
Cities must respond to submitted ADU plans within 60 days of receiving the application.
HOAs: Neither HOAs (Home Owners Associations) nor property CC&Rs (Covenants, Conditions, and Restrictions) can prevent the development of an ADU.
Fees: Cities will no longer charge impact fees for ADUs under 750 SQFT, and impact fees for ADUs larger than 750 SQFT shall be proportional to the size of the ADU in relation to the primary dwelling.
Size: Minimum size is220 square feet, or as low as 150 square feet if the city adopted a lower efficiency-unit standard by local ordinance.
Maximum size must be at least 850 square feet for attached and detached studio and one-bedroom ADUs and at least 1,000 square feet for two or more bedrooms.
In practice, an ADU might be limited to less than these minimum maximums by applying development standards, such as lot coverage and floor-area ratio. But another new provision prohibits the application of any measure that wouldn’t allow for at least an 800‑square foot, 16-foot tall ADU with 4-foot side and rear setbacks.
Converted ADUs may include expanding the existing structure of up to 150 square feet for ingress and egress.
Attached ADUs are limited to 50 percent of the existing primary dwelling.
Cities must approve new detached ADUs with only a building permit (as they do for converted ADUs) without applying any standard except for 4-foot setbacks, an 800-square foot max, and a 16-foot height limit.
UTILITIES: Depends on the size of the unit.
ADU More than 750 sqft: New utility connection required.
ADU Less than 750 sqft: No new or separate utility connection or related connection fee or capacity charge required.
PARKING: ADUS don’t require parking if created within an existing structure like a garage conversion. No replacement parking is necessary for the principal residence when a garage or carport is demolished or converted to build an ADU.
No parking is needed if any of the following criteria are met:
- ADU smaller than 750 SQFT
- Located within half a mile of a public bus stop or rail station, and the path of travel is publicly accessible.
- The ADU is on a street that requires on-street parking permits, but the permit has not been offered to the occupant of the ADU.
- Located within the boundaries of the permanent residential parking permit program and where the city does not offer parking permits to the occupant(s) of the ADU.
- Located within one block of a city-licensed car-share vehicle.
Check with your city for specifics.
DESIGN must be similar to the primary dwelling! Detached must incorporate the same or similar building materials and colors as a primary dwelling.
SETBACKS are only four feet. Exception—on more than a 10% slope, setbacks must be 15ft from rear and side.
SIZE restrictions:
Bedrooms: ADU shall include no more than two bedrooms.
Bathroom: ADU shall include no more than two bathrooms.
Kitchen: One kitchen (with permanent provisions for cooking and eating)
Storage: No requirements
Entryways: Must include separate exterior access from the primary dwelling. The front door cannot be oriented towards public streets.
Rental: ADUs must be rented for more than 30 days to keep neighborhoods from the AirBnB category.
Fire Safety: Per state requirements
The following table is published by the California Housing and Community Development (HCD) and includes the specific code sections:
