Pre-Designed and Pre-Approved Plans
Save time and money by choosing an existing set of plans and connecting directly with the architect, designer, or company. Plus, some locations have already reviewed plans for building code compliance, saving you even more time in the permitting process!
PLEASE NOTE: All existing ADU designs – even pre-approved plans – require planning for your property and other permit applications. You most likely need to hire a professional to complete this work. Not all designs work on all properties, so ask a professional before purchasing or using a design.
HEART's Free Eco-Smart Plans
The Housing Endowment and Regional Trust (HEART) of San Mateo County offers free ADU plans through their GLADUR program, including studios and 1- and 2-bedroom layouts. Plans are free to download and can be customized to fit your property. They are designed to comply with San Mateo County building code and have been pre-reviewed by several cities (some offer streamlined permitting for these plans). All GLADUR plans are designed to reduce both greenhouse gas emissions and energy costs.
ADU Plans Galleries
Some San Mateo locations have an online ADU Plans Gallery, offering a selection of site-built and/or prefabricated ADU designs. Galleries may include designs that have been pre-approved by local, state, or federal agencies, and using one of these plans may make you eligible for faster review.
Visit the Plans Gallery search page to see if your community has launched a gallery, or browse the statewide gallery to see the program’s entire selection of plans. NOTE: As of Fall 2024, this program is new and galleries are just beginning to launch. If your community doesn’t have one yet, check back soon!
