San Diego, CA Accessory Structures: ADU Impact Fees (2026)

Under California state law (Gov. Code § 65852.2(f)(3), enacted via AB 881/SB 13 in 2019), ADUs less than 750 sq ft are exempt from all local impact fees including water/sewer connection fees, capacity fees, public facilities fees, and transportation impact fees. ADUs 750 sq ft and larger pay impact fees proportional to the principal dwelling's size, not the full single-family rate. School district fees are subject to the same proportionality rules under Gov. Code § 65852.2(f)(2). San Diego implements these exemptions through the Development Services Department permit fee schedule. The city's Affordable ADU Bonus Program provides additional fee waivers and density bonuses for ADUs deed-restricted to households at or below 80% AMI for at least 15 years. SDG&E and the city's Public Utilities Department typically allow ADUs to share the principal dwelling's water/sewer service to further limit fees, with new connections required only when capacity is exceeded. Building permit fees themselves are not exempt and are assessed based on construction valuation.