La Jolla homeowners could soon build a second detached accessory dwelling unit on their property and pay lower impact fees under three bills Gov. Gavin Newsom signed Sept. 29.

The bills were part of a 34-law housing package Newsom signed that day, as first reported by lajolla.ca. Three measures carry specific consequences for La Jolla's predominantly single-family neighborhoods.

A new way to calculate ADU fees

SB 1117, authored by Sen. Sabrina Cervantes, D-Riverside, changes how cities charge impact fees on accessory dwelling units, or ADUs, larger than 750 square feet. Under existing law, ADUs at or below 750 square feet are exempt from impact fees. Larger units are charged proportionally based on the full square footage.

The new law narrows that calculation. Impact fees on ADUs over 750 square feet will apply only to the area exceeding that threshold. For a homeowner building a 1,000-square-foot ADU, fees would be based on 250 square feet rather than the full 1,000.

San Diego caps ADU size at 1,200 square feet, according to the city's Development Services bulletin. The fee change could apply to any ADU between 751 and 1,200 square feet built in La Jolla.

Two detached ADUs per lot

AB 956, by Assemblymember Sharon Quirk-Silva, D-Fullerton, requires cities to ministerially approve two detached, new-construction ADUs on a single-family lot. The previous state requirement was one.

San Diego's rules already allow one detached ADU, one converted ADU and one junior ADU on a single-family lot. AB 956 adds a second detached new-construction unit to that mix. Each detached ADU can be capped at 800 square feet and must meet four-foot side and rear yard setbacks.

One trade-off: if a homeowner builds two detached ADUs, the city is not required to also approve a junior ADU on the same lot.

Earlier cost disclosure for developers

SB 1014, by Sen. Tim Grayson, D-Concord, requires cities to provide a preliminary estimate of required onsite and offsite improvements within 30 business days of a developer's request. That estimate must include a list of improvement types and a good-faith cost estimate for any work the city itself would perform.

The bill also requires cities to deliver an itemized list of all required improvements within 30 business days of deeming a building permit application complete. Under the new law, cities cannot add improvement requirements after issuing that list unless the addition addresses a specific public health or safety risk. The estimates themselves are non-binding, according to the bill text.

Coastal permitting stays in place

La Jolla sits within San Diego's Coastal Overlay Zone, which adds a permitting layer. ADUs not fully contained within an existing structure require a coastal development permit, according to the city's bulletin. The new state laws do not change that coastal requirement.

Sen. Akilah Weber Pierson, D-San Diego, said in a press release from Newsom's office that the broader housing package reflects the need to "continue finding responsible ways to build more homes." Her comments addressed two other bills in the package, SB 344 and SB 958, rather than the ADU measures.

No La Jolla community planning officials have publicly commented on how the three bills will be implemented locally.