SB 1211 ADU cost calculator

Stick-built ADUs in California run $250–$450 per square foot, depending on city, finishes, and site conditions. A typical 600-sf detached ADU therefore costs $150K–$270K to build, plus $20K–$40K for site work, utilities, and permitting.

HCD-approved modular ADUs cut that meaningfully — $200K turnkey for the same square footage is achievable, and the SB 1211 ministerial pathway plays well with factory-built units that arrive pre-permitted.

For an 8-detached-ADU project, expect total project cost in the $1.6M–$3.2M range. Annual gross rent at typical California medians: $200K–$400K.