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Santa Cruz, California: ADU Regulations

Date Updated:


Are ADUs allowed in Santa Cruz:


Number of ADUs allowed:

Limited to one ADU per parcel.

Types of ADUs allowed:

Both attached and detached ADUs are permitted, however, a parcel may have EITHER a habitable accessory structure with a bathroom OR an ADU, but not both.

Lot size:

Must follow new construction guidelines.

ADU size:

ADU shall not exceed 10% of the net lot area up to a maximum of 1,200 sq.ft. Attached ADUs shall not exceed 50% of the existing habitable floor area of the primary dwelling and shall not exceed the maximum ADU floor area allowed for the lot. Accessory units that utilize alternative green construction methods that cause the exterior wall thickness to be greater than normal shall have the unit square footage size measured similar to the interior square footage of a traditional frame house.


No parking is required for an ADU, and parcels with an ADU are not required to provide any covered parking for the primary home. The number of parking spaces required for the primary home is not changed, and parcels must maintain or improve any existing substandard parking arrangement.


Detached ADUs
The side yard and rear yard setbacks for construction of detached single-story structures containing an accessory dwelling unit shall not be less than three feet and the distance between buildings on the same lot must be a minimum of six feet. Accessory dwelling units constructed above a garage built prior to 2017 shall provide side and rear yard setbacks of at least five feet. Accessory dwelling units higher than one story located within entirely new structures constructed after 2016 shall provide side setbacks of at least five feet and rear setbacks of at least ten feet. If any portion of an accessory dwelling unit is located in front of the principal single-family dwelling, then the front and side yard setbacks shall be the same as the principal single-family dwelling in the zoning district. An existing accessory building built prior to 2017 with a valid building permit or is a legal nonconforming structure that has less than required side or rear yard setback(s) may be converted into an accessory dwelling unit as allowed under Section 24.16.130. In addition, the building shall meet all other California Building Standards Code requirements including the alternative means and methods section as prescribed therein. Section 24.18.030(1) of the Municipal Code shall not apply.

Attached ADUs
Attached ADUs shall meet the same setbacks as the primary dwelling.

Note: Fire Department regulations should be assessed on a project by project basis.

Fire Safety:

Fire Sprinklers in ADUs are only mandatory if also present in or required for the primary structure.

Note: Fire Department regulations should be assessed on a project by project basis.


The ADU should share architectural compatible with the primary residence. Additionally, ADU doors, windows, and balconies should be situated to preserve privacy.

The two-story detached ADU shall limit the major access stairs, decks, entry doors, and windows to the interior of the lot, an alley, or the Monterey Bay Sanctuary Scenic Trail if applicable. Windows that impact the privacy of the neighboring side or rear yards shall be minimized.

If the design of the principal single-family dwelling has special roof features that should be matched on the detached ADU to enhance design compatibility, the maximum allowed building height of the accessory dwelling unit may be exceeded in order to include such similar special roof features subject to review and approval of the zoning administrator.


A one-story detached ADU shall be no more than 15' in height measured to the roof peak and shall not extend above and beyond the daylight plane having a height of 7' at each side or rear property line and extending into the property at an angle of 45 degrees.

A two-story detached ADU shall be no more than 22' in height measured to the roof peak.


The entrance to the ADU shall face the interior of the lot unless the ADU is directly accessible from an alley, a public street, or the Monterey Bay Sanctuary Scenic Trail.

Design review:

All development guidelines (setbacks, lot coverage, etc.) for the underlying zone district must be met. State ministerial review processes apply.

Note: Historic Neighborhoods or Districts should be assessed on a project by project basis.

Substandard Lots:

A Substandard Lot, as defined in Section 24.22.520, is any parcel that is smaller than the required square footage for the zone district or less than the minimum width required for the zone district (i.e. for a lot zoned R-1-5, a substandard lot would be smaller than 5,000sf, or less than 50’ wide):

The maximum allowable lot coverage for all structures shall be forty-five percent. Lot coverage shall include the footprints of the first floor, garage (attached and detached), decks and porches (greater than thirty (30) inches in height and not cantilevered), and any second-story cantilevered projection (enclosed or open) beyond two and one-half feet. Decks under thirty (30) inches in height or fully cantilevered with no vertical support posts do not count toward lot coverage for this purpose. Second-story enclosed cantilevered areas that project less than thirty (30) inches from the building wall do not count toward lot coverage. For such areas that project more than thirty (30) inches from the building wall, only the floor area that projects more than thirty (30) inches shall be counted as lot coverage.

The floor area for all second stories shall not exceed fifty percent of the first floor area for all structures, except in cases where the first floor area of the structure to which a second story is being added constitutes thirty (30) percent or less of the net lot area.

Continuous long walls parallel to the side property line with narrow side yards shall be minimized.

Landscaping shall be required at least for front yard areas
Structures, landscaping or other features shall incorporate methods to lessen the visibility of garages on a street facade.

When an attached New Construction accessory dwelling unit is proposed on a substandard lot in conjunction with a new single-family home, a Design Permit shall be required per Section 24.08.440.

Environmental Requirements:

Fire, Sanitation and Water Districts' approval requirements must be satisfied during the Building Permit process.

Note: Drainage and sewer connections should be assessed on a project by project basis.


Either the ADU or primary structure must be owner-occupied as evidenced by a homeowner's property tax exemption, or other documentation.

Permit Fees:

Allowed Zones:

The lot must be zoned Residential or otherwise have a General Plan designation of Residential. An exception is made for lots outside of the Coastal Zone which may be zoned for Agriculture.

Source Link:

Potential Rental Income:

According to, an accessory dwelling unit in Santa Cruz can generate $24,000+ per year in possible rental income.

Important Note: Rules and regulations are updated and changed frequently. It’s one of our jobs to be up to speed and navigate those regulations. Let us know if our website isn’t up to date or if you have any information that could help. Cheers!