Little house in the big woods |

Little house in the big woods

Accessory dwelling units - often referred to as granny units - have their own series of regulations that must be met when building.
Photo by Ethan Sexton/Unsplash

While the allowable use of granny units is being debated in Nevada County, there are still many property owners interested in investing in an Accessory Dwelling Unit (ADU) as they are officially called.

Be it over a garage or a stand-alone dwelling, the process for building an Accessory Dwelling Unit within county limits is not much unlike the process for building any other standalone unit.

Nevada County Director of Building, Craig Griesbach, said the process begins with drawing up plans, filling out an application and submitting both to the building department.

“In many ways it’s very similar to building a house,” he said. “You still need a spec plan, an application, setbacks etc. The only difference for granny units is there are some allowances that are not necessarily the case for the primary dwelling.

“For example, if you are building an accessory dwelling unit and the primary residence was built in the 1980s, fire sprinklers would not be required in the building. If the primary dwelling is built prior to certain requirements, the accessory dwelling would not be required to have them either. “

Griesbach continued, “There are other requirements making it easier to build. The number of required parking spaces is reduced, and there are waivers available for things like road mitigation fees. Depending on the type of construction, there are other allowances throughout the local code and as state mandated, that makes it easier for these buildings to be built.”

An accessory dwelling unit cannot exceed 1,200 square feet and is considered an accessory to an existing primary dwelling that already exists or is being built at the same time, whether that’s a detached building that’s independent or living quarters above a garage.

Some impact fees can be waived and if the dwelling is deemed as low-cost housing, some fees can be deferred until the project is complete, though Griesbach does not recommend it. “I never recommend doing that because if there is any point in time when you don’t have any money, it is at the end of your project.”

The timeline after submitting an application and plans to receive approval or comments that need to be addressed can take two to four weeks and then a passing inspection must be completed within two years with up to one-year extensions under special circumstances.

The use of granny units can be regulated by county and city statutes as well as individual neighborhood home owners’ associations. Griesbach said that generally the county regulation at this time is no short-term rentals are allowed, meaning renters must stay at least 30 days.

The county website has several documents to help property owners navigate the building process from check lists to step-by-step guides. For more information go to

Hollie Grimaldi Flores is a Nevada County resident and freelance writer for hire. She can be reached at

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