San Anselmo, Corte Madera update ADU rules

San Anselmo and Corte Madera are advancing updates to their regulations on accessory dwelling units.

The revisions are intended to align municipal code with state laws that have either taken effect or will take effect by 2025. The moves implement a large increase in the allowable number of detached ADUs on properties with multifamily dwellings.

In San Anselmo, the Planning Commission unanimously approved the changes at a meeting on Dec. 16. The updates will be heard by the Town Council on Jan. 4, said Heidi Scoble, planning director.

“The whole intention behind these state laws is to remove the barriers,” she said.

The town is projecting 160 accessory dwelling units, also called in-law units, to be permitted by 2031.

In Corte Madera, the Town Council approved the changes in a 3-0 vote on Dec. 17. Councilmember Eli Beckman and Mayor Pat Ravasio recused themselves.

“Eli runs a business to construct ADUs, and I am under contract to build an ADU,” Ravasio said.

The council also directed staff to remove the $300 filing fee from the town rules.

The key change in state law will increase the number of ADUs allowed on a property with multifamily housing from two to eight. The number of ADUs cannot exceed the number of apartments on the lot. They also must comply with development standards.

The changes also will increase the height allowance of ADUs when they are above a garage or a half-mile from a major transit stop. The changes will limit restrictions on front setbacks.

The new ordinance directs municipalities to ministerially approve proposed ADUs that meet the standards of 800 square feet and 16 feet tall with 4-foot side and rear setbacks. The revised ADU rules also remove the limit on a maximum number of bedrooms and allow a junior accessory dwelling unit to be created from a covered garage.

Corte Madera has permitted 63 accessory dwelling units since 2020, according to a staff report. Four remain under review.

Town officials have identified ADUs as a key strategy to hit housing target numbers for moderate- and low-income households. The town anticipates that 100 ADUs will be developed over the eight-year planning cycle that ends in 2031.

The state has mandated that Corte Madera allow 725 new residences during the planning period while also “affirmatively furthering fair housing.” Of those, 213 residences must be designated for very-low-income households and 123 must be offered at low-income rates. Another 108 homes need to be for moderate-income households, and 281 need to be for above-moderate-income residents.

San Anselmo is required to show it can accommodate 833 new residences during the eight-year planning cycle. Of those, 127 must be designated for extremely-low-income households; 126 for very-low-income; 145 for low-income; 121 for moderate-income; and 314 for above-moderate-income.

San Anselmo is projecting 959 new dwellings to be developed.