Overview
San Francisco is located in San Francisco County in California. San Francisco
has a total population of 805235 over a land mass of 46.87 Square Miles. When it
comes to ADUs, the city allows for 1+ ADUs on a given property, and a square
footage of 850-1,000 sf
Types of ADUs Allowed
Detached, Junior, Attached
Number of ADUs allowed
Under state law, each single-family home may now build at least one Accessory
Dwelling Unit (ADU). Owner occupied single-family parcels may build one
Accessory Dwelling Unit (ADU) and one JADU. Multi-family parcels, per every four
existing residential units, may build one Accessory Dwelling Unit (ADU), so long
as the existing units were legally established.
Property Requirements
Residential lots will be allowed to add up to 850 square ft. for a one bed ADU
or up to 1,000 square ft. for a two bed ADU, regardless of the underlying zoning
standards of the property. A Junior Accessory Dwelling Unit is allowed up to 500
square ft.. According to Califronia Residential Code, the minimum size of any
living unit is 150 square ft. (including ADUs and Junior Accessory Dwelling
Units). ~ AB-68
Types of ADUs Allowed
Attached ADU
An attached ADU is one that is attached to your house. Also know as Addition ADUs or “bump-out ADUs. These types of ADUs can be accessed from the primary house with a door in the connection point, but also can be independent of the main home.
Detached ADU
A detached ADU is not connected to your primary house. The dwelling needs to be within your property setbacks and allowable building size (both height and square footage).
Junior ADU
Junior Accessory Dwelling Units (JADUs) are named this way because they are small (up to 500 square feet).
In California, the recent state bills
AB68 and
AB 881 permits both an ADU and a Junior ADU (JADU) on the same lot with a proposed or existing single-family dwelling. This means you can have two units on your lot: ADU, and JADU.
Property Requirements
Ownership
Between between 2020 and 2025, owner occupancy requirements will not apply to
new Accessory Dwelling Unit (ADU)s. (applicable to new construction and
conversion units) ~ Updated: State Law SB-13
Number of ADUs Allowed
Under state law, each single-family home may now build at least one Accessory
Dwelling Unit (ADU). Owner occupied single-family parcels may build one
Accessory Dwelling Unit (ADU) and one JADU. Multi-family parcels, per every four
existing residential units, may build one Accessory Dwelling Unit (ADU), so long
as the existing units were legally established.
ADU Size
Single family and multi-family residential properties will not be subject to the
minimum lot size of the underlying zoning district or by ordinance for Accessory
Dwelling Unit projects. ~ AB68
Parking
Properties which convert an existing garage to an Accessory Dwelling Unit or
JADU will not be subject to replacement parking requirements. ~ AB68 & AB881
Update
Height
The main living space and the bedroom must have 7’-6” minimum ceiling heights.
The other rooms in the unit - kitchen, bathroom, hallways, laundry rooms - can
have ceilings as low as 7’-0”. Headroom is typically quite low when dealing with
adding ground floor units to hillside properties, or in existing garages - and
there are a number of exceptions for beams and sloped or furred ceilings - so
clearances should be should be reviewed during the pre-application meeting.
Reference 2013 SFBC/CBC Section 1208. Ceiling heights within the dwelling unit
are governed by the California Building Code.
Fire Safety
Fire sprinklers are an example of active fire protection, and are now required
in all new single family residential construction in California. In the case of
adding an ADU to an existing single-family home, you will most likely only be
required to add sprinklers to the new unit, adjacent spaces on the same floor,
and along the exit path - unless directed otherwise at your pre-application
meeting. Smoke and CO Detectors Smoke alarms are required to be installed in all
new dwelling units. These items must be hard-wired into the building’s
electrical system. Fire separation will be required between the ADU and any
adjacent garage or property line and between any living space above.
Utility Connections
One of the advantages to constructing an ADU within an existing building rather
than as a detached, free-standing structure is that the water and drain lines
are usually (relatively) easy to tap into so that the services can be extended
to the new unit’s bathroom and kitchen. ADUs do require their own electrical
service, with a dedicated electrical meter, circuit panel, and shut-off.Own
Aesthetic
Exterior modifications will be required to resemble those of the primary
structure. Interior conversions of existing space are not subject to this
requirement.
Set backs
The maximum required setback for a detached new construction ADU shall be no
more than 4 ft from the rear and side property lines. Setbacks will not be
required for ADUs and Junior ADUs converted from existing space that was legally
eastablished. Attached ADUs and conversions from existing space to be expanded
will be required to comply with the setbacks of the underlying zone. ~ Updated:
State Law AB-68
Design Review
It was a discretionary review process, but is now updated in 2018 to comply with
State Law. California now requires that ADUs be approved through a ministerial
process or "by right".
Next Steps
To get started on your ADU, here are some first steps.
Call Your City
Search Google for your city’s contact number. eg “City of {Phoenix} Residential Permits Contact Number”
You can call the main line and get directed to the permitting department.
Ask these questions...
1) Can I put a secondary home on my lot (Accessory Dwelling Unit)?
2) What are my livable setbacks, and ADU size regulations?
3) Can I put a prefabricated guest house on my property?
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