Accessory dwelling units (ADUs) are allowed on any parcel where the zoning district or General Plan allows residential uses, and there is an existing or proposed primary dwelling. ADUs can be attached or detached from the primary dwelling, new construction, or converted from existing space, and can be standard or junior ADUs. For parcels located within the California Coastal Zone, please contact the Planning Division at planning@co.del-norte.ca.us for details. For more information see Types of ADUs.

Key Considerations

Structure Legality. Only structures constructed legally may be converted to ADUs. Illegal structures may also be converted to ADUs but will be treated as new construction projects with associated requirements. Property owners seeking to legalize ADUs in illegal structures that cannot meet the current building code may contact the Building Inspection Division at building@co.del-norte.ca.us.

Septic Requirements. Parcels on septic may require septic system upgrades and should contact the Environmental Health Department at environmental-health@co.del-norte.ca.us for more information.

Short-Term Rentals. Short-term rentals (rentals less than 30 days) are not allowed in ADUs. A property may rent the primary residence and reside in the ADU or rent the ADU for periods greater than 30 days.

Permits Required

Most ADUs require only a building permit and are reviewed within 60 days of submittal.

Additional review may be required before a building permit may be issued for certain changes to non-conforming dwellings, or ADUs located in the Coastal Zone.

Number of ADUs Allowed

Parcels with single-family dwellings: one attached ADU, one detached ADU, and one JADU are allowed per single-family dwelling. Note that if both an ADU and JADU are proposed to be attached to a single-family dwelling, multifamily building code requirements may apply. Contact the Building Inspection at building@co.del-norte.ca.us with any questions.

Parcels with multifamily dwellings: two detached ADUs are allowed which may be attached to each other, and up to 25% of units can have an ADU converted from existing non-livable space such as a garage or storage area.

ADU Size

JADU: Minimum 150 square feet, maximum 500 square feet

Conversion ADUs: Up to 1,200 square feet. An additional 150 square feet. may be addressed to meet ingress/egress requirements.

New Construction ADU: Minimum 150 square feet, maximum 1,200 square feet

Parking

Parking is not required for Conversion ADUs or JADUs. Property owners converting garages to ADUs do not need to replace lost parking spaces.

New Construction ADUs require one new parking space except in the following locations:

Building Envelope

New construction ADUs have special setbacks and height standards that define the building envelope for these structures.

Minimum Setbacks from Property Lines
- Minimum front setbacks: standard for the zone district
- Minimum side setbacks: 4 feet
- Minimum rear setbacks: 4 feet
- Minimum separation between ADU and other structures: 5 feet or the minimum distance required by the Building Code, whichever is greater
Maximum Height
- Attached ADUs: standard for the zone district (usually 35 feet outside of the Coastal Zone and 25 feet within the Coastal Zone.
- Detached ADUs: 16 feet in most cases
- ADUs above Detached Garages: 25 feet
Maximum Lot Coverage
- An ADU shall comply with the lot coverage requirements of the applicable zoning district, except that in the case where the allowable site coverage would preclude an accessory dwelling unit, one attached or detached accessory dwelling unit with a maximum size of 800 square feet, regardless of the number of bedrooms, shall be allowed.