San Mateo County’s Housing for All initiative collects resources that aid in the creation of accessory dwelling units (also known as second units or ADUs). They offer a variety of resources that are useful in San Mateo County and beyond.
While this web page is oriented toward San Mateo County homeowners, many of the materials will be broadly useful to other parties and in other locations. It may also serve as a model for other cities and counties.
Granny flat, in-law suite, accessory dwelling unit (ADU), converted garage, backyard cottage, basement apartment — whatever you call it, get inspired to build one in San Mateo County, or elsewhere. This guide for homeowners offers an overview of second unit types with case studies and design ideas.
This workbook was created as a resource to help homeowners build a second unit. It provides a detailed, step-by-step approach to the entire project — from getting started to becoming a landlord.
The workbook was designed to provide useful information and reduce the uncertainty in what can feel like a complicated process. Sections include:
- How to get started
- Designing your second unit
- Budgeting and finance
- Permitting and approvals
- Move in (including resources on how to rent successfully)
Direct homeowners to this resource to help them estimate the cost of converting part of their home into an accessory dwelling unit (ADU) or constructing a rental unit.