Frequently Asked Questions about ADUs

DEFINITIONS

• What is an Accessory Dwelling Unit (ADU)?

An ADU is an independent dwelling unit with a dedicated exterior entrance that provides complete living facilities for a household, including permanent provisions for living, sleeping, eating, cooking, and sanitation. ADUs can be New Construction or Conversion from existing habitable or non-habitable space. In order to meet this definition, ADUs must have a full kitchen, including a built-in permanently installed cooking appliance, and a full bath with facilities for sanitation and bathing. Structures without all these facilities are not considered ADUs.

• What is a Junior ADU (JADU)?

A JADU is a dwelling unit contained within the walls of a proposed or existing dwelling unit, with a dedicated exterior entrance. JADUs can be converted from either habitable space (such as an existing bedroom) or non-habitable space (such as a garage or storage area). JADUs may not be more than 500 square feet in size, including additions of no more than 150 square feet. JADUs must include all of the following facilities: independent provisions for living, sleeping, eating, and cooking (area meeting the definition of an efficiency kitchen), and shared or separate sanitation facilities with the main dwelling unit. Residential areas without all these facilities are not considered JADUs.

JADUs are not required to have interior access to the primary dwelling.  Note that JADUs without interior access to the primary dwelling are considered independent units under the building code, with associated requirements for fire separation.

• What is a "Kitchen" vs. "Efficiency Kitchen" and Which is Required for ADUs?

A "kitchen" is any room or portion of a room used or intended or designed to be used for cooking and/or the preparation of food and containing all of the following: a sink having a drain outlet larger than 1.5 inches in diameter, a refrigerator larger than 2.5 cubic feet, a built-in permanent cooking appliance typically including a full-size gas or 220-volt electric range/oven with a range/hood ventilation system, and space for food preparation and storage.

An "efficiency kitchen" is a limited kitchen facility that includes a sink, a refrigerator, small electric kitchen appliances that do not require electrical service greater than 120 volts, an appropriately sized food preparation counter, and storage cabinets. Gas or propane cooking appliances are not allowed.

ADUs are required to have kitchens. JADUs are required to have efficiency kitchens. Primary dwelling may include one efficiency kitchen in addition to one kitchen, as long as the efficiency kitchen area has interior access to the rest of the dwelling. If a dwelling includes a JADU, then an additional efficiency kitchen outside the JADU is not allowed.

BASIC RULES FOR BUILDING AN ADU

• Can I Build an ADU on My Property?

Contact the Planning Division at planning@co.del-norte.us or call (707) 464-7254 to learn whether your parcel is eligible for an ADU.  Planning Division staff will need to have the parcel's Assessor Parcel Number to provide ADU eligibility.

• Is There Any Limit on the Number of ADUs That Can Be Built in the County, or in my neighborhood each year?

No. There is no overall limit on the number of ADUs in the unincorporated County.

• Do I Need to Live on the Property?

It depends. Owner occupancy is required only if there is also a JADU on the property.

• Can I Use a ‘Tiny Home’ as an ADU?

Not if the “tiny home” is mobile. To meet building code requirements for habitability, every ADU must be placed on a permanent foundation and connected to utilities. ADUs may be conventional construction, pre-fabricated, modular or a mobile home installed on a permanent foundation. The ADU may also be created by converting space in an existing structure. See Types of ADUs page for more information. 

Under California law, a tiny home mounted to a chassis with wheels is classified as a Recreational Vehicle (RV), eligible only for occasional or seasonal use, and cannot be used as a permanent residence.

• What Are The Rules Regarding the Conversion of Non-Habitable (Non-Living) Space Such As Garages And Storage Areas?

Non-habitable space can be converted to an ADU, following the rules regarding Conversion ADUs. Some storage spaces and garages in new homes may be set up with wall construction and limited pre-run electrical and plumbing utilities to allow for easier future conversion to ADUs.

An underfloor storage area or crawlspace with a dirt floor is not considered to be built space. Development of an underfloor area into an ADU would constitute a New Construction ADU project rather than a Conversion ADU. A JADU cannot be created from an underfloor storage area, because the underfloor area is not located within the walls of the primary dwelling.

PLANNING AND BUILDING PERMIT PROCESS

• What Permissions Do I Need to Legalize or Build an ADU?

If you have an existing ADU that was built without permits, or you would like to create a new ADU, you will need to first verify with the Planning Division whether an ADU is allowed.  If the ADU is allowed, you will need to obtain a building permit from the Building Inspection Division. Some ADU projects may require discretionary planning approval before a building permit can be obtained, but this is rare. Certain ADUs inside the Coastal Zone require Coastal findings that are included in the building permit review. Some projects may also require additional permits related to grading or any septic system modifications that might be necessary. 

If you have an existing ADU on your property that was constructed with permits before the County had an ADU ordinance in place, then you do not need to obtain a permit to officially designate that existing space as an ADU.

• There Is an Accessory Structure On My Property That Was Not Constructed With Permits. Can I Convert It Into an ADU? There Is an ADU That Was Built Without Permits On My Property. Can I Legalize It?

The first step is to verify with the Planning Division whether an ADU is an allowable use on your parcel.  If it is an allowable use, and if the accessory structure can be brought up to the current building code, the structure may be considered.   Zoning standards such as height or setbacks will need to be considered as part of the overall consideration for the ADU.

• The State Law Says That There is a 60-Day Review For ADU Permits. Does That Mean I Will Receive My Permit 60 Days After I Submit an Application?

Potentially. When you submit an ADU building permit application, the Planning Department staff has 60 days to review that application and issue either a building permit or a letter stating any further submittals or corrections to plans that are required. Each time you resubmit an application with corrections, the 60-day review clock re-sets. When you submit a complete and correct ADU building permit application, you will receive a building permit within 60 days of that submittal.

• Is a Public Hearing or Public Notice Required?

Not normally. ADUs that conform to site standards usually require only a building permit, with no public hearing or public notice. In the coastal zone, public notice may be required for ADUs requiring a coastal development permit or ADUs in certain non-residential zone districts.

• Can I Build the ADU First and a Primary Dwelling Unit Later?

Potentially.  When only one dwelling is constructed on a parcel, it is considered a primary dwelling, and standard permit process, development standards and fees apply. However, this initial dwelling can later be “converted” to an ADU if it meets the maximum size and other criteria, and a new primary dwelling can be constructed.

DEVELOPMENT STANDARDS

• What Size ADU Can I Build?

The maximum allowed size for New Construction ADUs is 1200 square feet, depending on the parcel size, type of ADU, number of bedrooms in the ADU, and the floor area and lot coverage of the existing structures on the parcel. 

• How Do You Calculate ADU Square Footage?

The square footage that counts toward the size of the ADU includes habitable square footage measured from exterior walls. Garages do not count toward ADU size, even if the ADU is built above or concurrently with a garage, and even if the garage is intended to serve residents of the ADU.

• I Have Already Met/Exceeded the Allowed Building Square Footage or Lot Coverage On My Property. Can I Build an ADU?

Yes. You may construct an ADU up to 800 square feet, with a height of 16 feet and side and rear setbacks of 4 feet, even if you have already met or exceeded the floor area or lot coverage percentage allowed for your parcel’s zone district.

• Does an 800-Square Foot ADU Count Toward the Total Floor Area On My Property?

No. The 800-square foot ADU allowance functions as a “credit” that can be deducted from the overall floor area. For instance, let’s say your maximum allowed building floor area on a parcel is 2000 square feet, and you have an existing primary dwelling that is 1,200 square feet. In this example, if you construct an 800-square-foot ADU, this square footage would not count toward the maximum allowed square footage, and therefore an additional 800 square feet of building area would still be allowed on this parcel.