Sunnyvale ADU Guide (2026): Rules, Fees, and Building a Backyard ADU
Sunnyvale rewrote its ADU rules in 2025 and updated them in July 2026: up to 1,000 sq ft, no parking, and a building-permit-only path up to 800 sq ft. Here's what you can build and what the city charges.
San Jose ADU Guide (2026): City Rules, Fees, and Permits
San José lets you build an ADU under City or State standards, with no parking required and no impact fees up to 750 sq ft. Here's what you can build, what the city charges, and how the permit works.
San Mateo ADU Guide (2026): Rules, Fees, and Building a Backyard ADU
San Mateo updated its ADU rules in March 2026: up to three extra units on a single-family lot, no parking, and a building-permit-only process. Here's what you can build and what the city charges.
San Francisco ADU Guide (2026): Rules, Permits, Fees and Costs
Most San Francisco homeowners can add a backyard ADU up to 850-1,000 sq ft and 18 feet tall, with no parking and a 60-day review. Here's which program to use, what it costs, and how the permit works.