Costs
How Much Does It Cost to Build an ADU in 2026? Complete Cost Guide
Relying on generic square-foot estimates is the fastest way to derail an accessory dwelling unit budget before breaking ground. When homeowners ask how much does it cost to build an adu in California, broad market ranges between $150,000 and $400,000 provide very little clarity. Baseline estimates rarely reflect site realities. A dependable budget always depends on property infrastructure, sewer lateral connections, and local municipal mandates rather than arbitrary formulas.