California is so eager for homeowners to build ADUs, it’s helping them save on architect fees

California cities are expanding pre-approved ADU plan programs to help homeowners slash architectural costs and accelerate construction of accessory dwelling units.

The initiative represents the state's latest effort to address its housing crisis by removing financial barriers that have historically deterred property owners from building additional housing on their lots.

Under these programs, homeowners can purchase ready-made architectural plans for between $1,000 and $7,000, significantly less than the $5,000 to $15,000 typically required for custom designs.

Some plans developed by nonprofits like HEART of San Mateo County are available at no cost.

The pre-approved plans also eliminate weeks of waiting for permit approval, streamlining the development process for property owners.

The cost savings come at a crucial time, as ADU construction remains expensive despite regulatory reforms.

Building costs typically run $500 to $600 per square foot, meaning a 600-square-foot unit costs around $300,000 before factoring in utility hookups and site preparation.

ADU advocacy groups emphasize that reducing upfront costs allows homeowners to allocate more resources toward actual construction.

The pre-approved plan initiative builds on previous state legislation that has made ADU development easier, reflecting California's broader strategy to encourage residential density and address housing shortages through policy interventions at the local level.