Can I put a Accessory Dwelling Unit (ADU) on my property?

ADU’s can provide great benefits to many different people and living situations and the Nevada County Planning Department would like to get the information out on the benefits of ADU’s and the process to construct this type of housing option. 

What is an ADU? Accessory Dwelling Units, also called second units or "granny units", can be an extremely beneficial and affordable option to provide additional housing units on a residential property. An ADU is an accessory dwelling unit with complete independent living facilities for one or more persons and can include the following:

• Detached: The unit is a separated structure from the primary residence.

• Attached: The unit is attached and/or contained within the primary residence.

• Converted Existing Space: Space (e.g., master bedroom, attached garage, storage area) on the property of the primary residence that is converted into an independent living unit.

• Junior Accessory Dwelling Unit (JADU): A specific type of conversion of existing space that is contained entirely within an existing single-family residence.

Are ADU’s affordable? ADU’s tend to be significantly less expensive to build and offer benefits that address common development barriers such as land acquisition and construction costs and environmental studies. Because ADU’s are built on lots with existing or proposed housing, they do not require the purchase of new land, additional parking or other costly infrastructure required to build a new single-family home. Junior ADU’s and attached ADU’s are contained inside existing single-family homes and require relatively modest renovations and are much more affordable to complete. ADU’s are often built with cost-effective one or two-story wood frames, which are also cheaper than other new homes and can be attached to garages, storage buildings and other accessory structures on a site. Additionally, prefabricated ADU’s can be directly purchased and save much of the time and money that comes with new construction.

What are the benefits of an ADU? ADU’s can provide as much living space as apartments and condominiums and work well for couples, small families, friends, young people, and seniors. ADU’s also give homeowners the flexibility to share independent living areas with family members and others, allowing seniors to age in place as they require more care, thus helping extended families stay together while maintaining privacy. The space can be used for a variety of reasons, including adult children who can pay off debt and save up for living on their own. Homeowners can construct an ADU on their lot or convert an under utilized part of their home into a Junior ADU or attached ADU. This flexibility benefits both renters and homeowners who can receive extra monthly rent income.

How do I get started? The process to construct an Accessory Dwelling Unit can seem daunting and the information on how to get started can be hard to find. The Building Department and Planning Department have created two new informational pamphlets that provide information regarding Accessory Dwelling Units. One of the informational handouts is the "Fast Facts" informational sheet to provide a quick starter guide for exploring the basics of ADU rules, regulations, costs and fees. The second handout is called "Frequently Asked Questions" and is intended to provide more detailed information and answers for people who decide to pursue constructing an Accessory Dwelling Unit. 

Areas that are zoned to allow single-family residential homes, also allow an Accessory Dwelling Unit, without subdividing your property. An accessory dwelling unit is ministerial permitted, regardless of minimum parcel size and zoning densities on all parcels within RA, R1, R2, AE, AG, FR, and TPZ zoning districts, subject to zoning compliance and building permit issuance. Additional standards, including maximum allowable sizes, can be found in Sec. L-II 3.19.1.

  • Where a property does have available density (meaning the property is at least twice the minimum allowable lot size), an accessory dwelling unit may be permitted in RA, R1, R2, AE, AG, FR, and TPZ zoning districts without limiting the size of the unit, subject to an Administrative Development Permit. Additional standards apply which can be found in Sec. L-11 3.19.2. For questions about allowed density, please contact the Planning Department at 530-265-1222 option 2 or
  • Employee Housing that does not satisfy zoning density is allowed as a permitted use subject to building permit issuance and zoning compliance for 4 or less attached or detached units where the employee is engaged in on-site employment (or on a site under the same ownership) relative to a resource-based use (i.e. mineral extraction, timber harvesting and agricultural operations). Employee housing for 5 or more employees require a State issued permit. Section L-II 3.10 of Zoning Ordinance provides specific detail regarding the limitations on this type of housing.
  • On commercial and industrially zoned properties, a maximum four dwelling units per acre are allowed, in conjunction with development of the intended commercial or industrial use. Establishing dwelling units in a commercial or industrial zoning district requires a Use Permit.

Accessory Dwelling Units (ADU) Frequently asked Questions  (PDF)

Accessory Dwelling Unit Fast Facts (PDF)

The Planning Department and Building Department staff are available to further consult with perspective applicants and answer project specific questions regarding this attractive housing option.

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1. What are the fees for different Planning Department services?
2. How do I make a request for project notification?
3. What is my zoning?
4. How can I change my zoning?
5. How do I get a map of my property?
6. Can my property be subdivided?
7. Are there any environmental constraints on my property?
8. What are my building setbacks?
9. Can I put a Accessory Dwelling Unit (ADU) on my property?
10. Who is authorized to prepare biological inventories in the unincorporated County?
11. How do I file a land use complaint?
12. Is my property in a floodplain?
13. Can I have animals on my property?
14. What are the timelines for processing land use permits?