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Adding Housing to Your Housing, Part 1

Updated: Dec 8, 2023

Adding Housing to Your Housing, ADU

Inspired by the state-driven Regional Housing Need Allocation program requirements which were made considerably more robust in 2017, there are now a lot of options available to homeowners wanting to add more housing units to their properties these days. These include lot splits, duplexes and ADU’s, which can be added with varying levels of complexity depending on which route you take.

The main two vehicles for adding housing or splitting your residential parcel to create more housing are the ADU Rules and California SB9, which went into effect in January of last year.

The California ADU Rules are a group of senate and assembly bills together which are constantly being added to and refined, including one being considered right now that would allow homeowners to sell their ADU’s separate from their house.

Under the ADU guidelines, so long as their property meets key core requirements anyone who owns a SFR can build an ADU on the property plus a junior ADU in the house, which usually involves a bedroom or garage conversion. And they can also add an efficiency unit in another bedroom with a “hotel kitchen” setup that includes a refrigerator, microwave and outlet for a hot plate. And if someone owns a duplex, they can have an ADU for each unit.

Accessory Dwellings only need a building permit which is handled as an administrative application through the building department, unless the property is either non-conforming or in the coastal zone, which then requires discretionary review. An ADU is detached from the home and generally varies between 800 SF and 1200 SF, depending on the size of the lot. By contrast, a Junior ADU runs between 150-500 SF and is contained within the footprint of the main residence. And under the new guidelines, all of the new housing can be on the same water, electric and gas meters, and connected to the existing septic system, provided its capacity can accommodate or be expanded to handle the new bedrooms.

ADU’s are required to meet the same front yard setback from street as required for the main house per the zoning district, but side and rear yard setbacks are reduced to 4 feet, unless the ADU is over 16’ height, which increases the setbacks to 8’ on the sides and rear and 3’ from the house. And if the structures are close to the setbacks on the side and rear yards you may be required to get a survey. Under the new rules, there is no longer any requirement that the owner live on the property, but you still can’t use an ADU as a vacation rental.

For parking, you need to provide 1 space for an ADU unless the property is located within ½ Mile of a transit stop. This exemption doesn’t currently apply if your property is located within the Coastal Zone, but the state is considering overturning that policy. And if you convert a garage to create a Junior ADU, you don’t need to replace the parking spot that was displaced. In some areas such as Pleasure Point where they have permit parking, you need an additional parking spot, but the County is talking about doing away with that requirement as well.

There is a fair amount of overlap between the ADU rules and SB9, but generally speaking, an SB9 application is a much more complicated and time-consuming process, which for the moment I will save for a separate discussion.

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