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What Are The Size Requirements For My New ADU?

Updated: Jan 26, 2022

In September 2020, a new California Department Of Housing handbook regarding laws, rules, and regulations of newly built ADU’s was released. This article regards the laws of only the state of California, cities in California with separate ADU ordinances may be different.

Is There A Minimum Lot Size Requirement? According to the California Department of Housing Handbook, no, there is not a minimum lot size requirement. While state governments can have standards for ADUs, these standards can’t include minimum lot size requirements. But, building and safety standards are still in play and ADUs must adhere to those laws.

What is a Statewide Exemption ADU? A statewide exemption ADU is an ADU of up to 800 square feet, 16 ft. in height and with 4-foot side and rear yard setbacks. ADU laws require that no lot coverage, floor area ratio, open space, or minimum lot size will get in the way of the construction of a statewide exemption ADU. ADU laws also allow the construction of a detached new construction statewide exemption ADU to be combined with a junior ADU within any zone allowing residential or mixed uses regardless of zoning and development standards imposed in an ordinance.

Can Minimum And Maximum Unit Sizes Be Established For ADUs? Yes, the government can establish minimum and maximum size requirements for ADUs. However, maximum unit size requirements must be at least 850 square feet and 1,000 square feet for ADUs with more than one bedroom. For cities without an ordinance, maximum unit sizes are 1,200 square feet for a new detached ADU and up to 50 percent of the floor area of the existing primary dwelling for an attached ADU (at least 800 square feet).

The conversion of an existing ADU or primary residence to a new ADU is not subject to size requirements. For example, an existing 3,000 square foot barn converted to an ADU would not be subject to the size requirements. If you want to expand your ADU in any way, then you may be subject to the size requirements.

Neo Builders Inc. is an experienced construction company with a specialty in building ADU’s. Building an ADU with Neo Builders will increase your monthly cash flow in a stress free and organized process. Check out our Los Angeles rules and regulation page for more details.

Don’t wait, make the call today for a step towards financial freedom. An initial consultation and quote are FREE of charge.

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NEO Builders Inc.

3940 Laurel Canyon, Studio City #394, 91604

License #: 1061134

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