For a lot of San Diego County homeowners, yes. Governor Gavin Newsom signed Senate Bill 1117 on September 29, 2026, and it fixes a frustrating fee rule for accessory dwelling units, or ADUs. As the San Diego Union-Tribune explained on October 14, ADUs of 750 square feet or less were already exempt from impact fees, but in many cities, going even slightly over meant paying fees on the entire unit. Under the new law, the first 750 square feet stay fee free and cities can only charge for the space above that, for up to two ADUs on a lot. My short answer: a roomier backyard home just got more affordable in many parts of the county.
How much could you save? It depends on where you live. The Union-Tribune ran the numbers for La Mesa, where a 1,200 square foot ADU would save around $2,800 under the city's current fees. Most communities in San Diego County limit ADUs to 1,200 square feet, so this is about making family sized units practical, not building giant ones. The law applies to every California city, including charter cities, and like most new state laws it takes effect January 1, 2027.
What about the city of San Diego? City homeowners already have one of the friendliest setups around. According to the City of San Diego, the first two ADUs on a property are exempt from development impact fees regardless of size. The city's 2025 Annual Report on Homes shows 2,285 ADU homes permitted in 2024, the most ever in a single year and 26% of all homes permitted citywide. So SB 1117 matters most in the other county cities that charge ADU impact fees today.
Why do I love ADUs? As a broker and an investor, I know how much a well planned backyard home can change the math on owning in San Diego. It can bring in rental income to help with the mortgage, give family a place to stay close by, or become a home office. With no new land to buy, it is one of the most efficient ways to add living space to a property you already own, and homeownership is still the best long term wealth builder there is.
A few tips before you start. Homeowners, get the current fee schedule from your city first. The new rule covers impact fees, not utility connection fees or capacity charges, and permit costs still apply. A slightly larger ADU with a second bedroom may now pencil out where it did not before. Buyers, look at lot size and layout with a future ADU in mind. Sellers, if your property has room for one, highlight that flexibility. Always confirm the rules for your property with your city and qualified professionals.
If you want to talk through whether an ADU makes sense for your property or your next purchase, I'm your realtor, let me know when you need me.
Quick answers
What is SB 1117? A California law signed September 29, 2026 that limits impact fees on ADUs over 750 square feet to only the space above 750 square feet, for up to two ADUs on a lot.
When does it take effect? January 1, 2027.
Does it change anything in the city of San Diego? Very little. The city already exempts the first two ADUs on a property from development impact fees regardless of size.
How much could I save? It varies by city. The Union-Tribune estimated about $2,800 on a 1,200 square foot ADU in La Mesa.
Read the original article: https://www.sandiegouniontribune.com/2026/10/14/california-just-passed-a-ton-of-housing-laws-heres-how-they-will-affect-san-diego/
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Image credit: Keizers via Wikimedia Commons, CC BY-SA 4.0