Q & A

What is an ADU?
An accessory dwelling unit, or commonly referred to as “ADU”, is a second permanent dwelling on the same property as a primary dwelling.  ADUs provide complete independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation.
Is an ADU allowed on my property?
All properties with an existing or proposed residential dwelling may have an ADU.  The ADU may be constructed prior to, at the same time or after the primary dwelling unit.Properties with two-or more attached units (e.g. duplex), may construct up to two detached 800 sf ADUs on a single property.
What size of an ADU is allowed?
All residential properties are allowed to construct an ADU of at least 800 sf.  In some cases, a larger unit up to 1,200 sf may be allowed.
What is the difference between an attached ADU and a detached ADU?
An attached ADU is a living unit that is either contained within the walls of the primary dwelling i.e. conversion of garage or bedroom or is newly constructed and shares a common wall with the primary dwelling.
What are the setbacks requirements for an ADU?
Detached ADUs must have a minimum of four foot side and rear yard setback.  If the ADU is created through the conversion of space in an existing detached structure, i.e. garage, the existing setback may be maintained provided it is sufficient for fire safety. Attached ADUs shall maintain a five-foot side yard setback and a 20-foot rear yard setback.  In some cases, the rear yard setback for attached units may be reduced to 10 ft.  If your project requires a reduced rear yard setback, contact the Planning Division of the city where your property is located to see if your property qualifies. There may be other factors such as easements that will increase the required setback. Additionally, it is not recommended to build right up to the setback line.  Many times, during construction if the structure appears too close to the setback, the property owner may be required to have the property surveyed during the inspection process.  To find out if your property has easements that need to be considered, please refer to your property’s title report.
What is the height limit of an ADU?
The maximum height allowed for a detached ADU is 18 ft with an additional 2 ft allowed for accommodating roof pitch.  If the ADU is attached to the primary home, the maximum allowed height is 30 ft.
What are other factors when considering an ADU?
  • Window placement is restricted if the ADU is within 15 ft. of a residence on an adjacent
  • parcel and two-story units must use obscure glass on second story windows if the unit is within 10 ft of the property line.
  • Attached ADUs and junior ADUs must have an entrance separate from the entrance to the primary dwelling.
  • Properties with protected trees (such as oak trees) may require special permitting.
  • Properties near waterways i.e. creeks, drainage areas or in areas designated as 100-yearflood zone, may have restrictions.
Can I rent the ADU or does it have to be occupied by family?
The unit does not have to be occupied by family.  The ADU may be used for rental property but it may not be used for short-term rentals (less than 31 days).
Is additional parking required for an ADU?

Additional parking, or replacement parking when converting a garage, is not required.

Can an existing garage be converted into an ADU?
Yes, if it is a legal structure. However, it must meet current building and fire codes since it will beconsidered a change in use.  To be considered an ADU, the unit must provide provisions for living, sleeping, eating, cooking, and sanitation.
Will my property taxes increase?
If the Assessor’s Office reappraises your property due to a change in ownership or new construction, you will be notified by mail of the new assessed value. This notification is known as a ‘Notice of Supplemental Assessment.’
What is the minimum lot size for an ADU?
There are no minimum lot sizes for accessory dwelling units per California state code. Even if there is a coverage ratio maxed out on your property, you are still allowed to build at least an 800 sqft ADU.
Can I convert an existing garage into an ADU?

Yes.

How many ADUs can I build?
New state laws permit two ADUs on a single-family zoned property; One full Accessory Dwelling Unit (ADU) and one Junior Accessory Dwelling Unit (JADU).
How large an ADU can I build?
Generally, you will be able to build at least a 1000 sqft ADU, and up to 1200 sqft in some cases. Some cities have slight changes in their dimensions, so we must verify city-by-city on their regulations.
How many bedrooms are allowed in an ADU?
There is no maximum number of bedrooms provided the floorspace of the unit does not exceed the allowed size.
How is the floorspace of the ADU calculated?
The floorspace of the ADU will include all areas accessed from within the unit.  For example, if the
unit has an attached garage that is accessible from within the ADU, the floorspace will include both
the unit and the garage.  If the garage is not accessible from within the ADU, the floorspace would only include the ADU.
How many ADUs are allowed?
Properties developed with a single-family residence may have one standard ADU (either attachedor detached) and one Junior ADU.
What is a Junior ADU?
A junior ADU is space within the “envelope” of the primary dwelling which is converted into separate living space, typically a bedroom or attached garage.  To be considered a JADU, the following requirements must be meet:

  • May be no larger than 500 sf
  • Created through the conversion of existing or proposed space within the primary residence 
  • An attached garage may be converted into a JADU
  • Have a direct entrance to the outside
  • Provide an efficiency kitchen 

1. Sink drain maximum waste diameter of 1.5 inches
2. Cooking facilities with appliances that do not require more than 120 volts, natural orpropane gas
3. Food preparation counter and storage cabinets that are reasonable size in relation to the size of the JADU

  • May include separate sanitation facilities, or may share sanitation facilities with the existingstructure
  • Either the primary dwelling or the JADU must be occupied by the property owner

Property owner must record a deed restriction to the property’s title prohibiting the sale of theJADU separate from the sale of the primary residence and restricting the size and attributes of the JADU.
Does an ADU require separate utilities?
Separate service is not required but your utilities will need to be sized to meet the additional demand or load of the new ADU. Some properties may need to upgrade utilities for more capacity.
You will need to contact your specific service providers on capacity questions.
Is solar energy required for ADUs?
ADUs must meet energy code requirements including the provision to provide solar. The photovoltaic system can be installed on the ADU, or on the main house.
Are fire sprinklers required in an ADU?

If the primary dwelling has sprinklers, the ADU will be required to have sprinklers.

Do I need a permit to create the ADU?

A building permit is required.

How much is a building permit for an ADU?
The building permit fee varies depending on the size of the unit and whether it is a conversion, new structure or manufactured unit.  In addition to the building permit fees, some projects also pay impact fees.  To encourage the development of ADUs, impact fees are waived for units 749 sq. ft.or less and units 750 sf and greater pay a reduced rate. 
To obtain a fee quote, contact the Building Division of your property location.