The cost to build ADUs is approximately 50% less than a traditional house. They are generally smaller than the original house and can be constructed offsite using modular design. Comparing ADUs and apartments on Craigslist, ADUs rent for less for the same amount of space. In the eastern half of the US, ADUs tend to be attached to the home space whereas ADUs in the western US are generally separated from the main house. There are pre-approved builders in San Jose and other cities which help streamline the permitting process. 

In addition to offering a homeowner a stream of income from tenants, there are many benefits to adding an ADU. They can keep owners in their homes longer because of rental income which allows them to build wealth over time. By providing more affordable housing, the community becomes more diverse as low-income residents such as students, small families, and seniors can more easily afford the lease on an ADU. Residents can remain in the community rather than move away from their jobs and drive longer commutes. These small houses or attached places allow flexibility to homeowners for seniors to age in place, caregivers, or college students to have their own space.

ADU Resources

Casita Coalition statewide organization that removes barriers to constructing ADUs and helps identify innovative program designs, codes and policies.

Umpqua Bank works to build community through environmental, social, and governance guidelines (ESG) 

Housing Trust Silicon Valley  helps homeowners build homes to rent in their backyards

Self-Help Federal Credit Union  helps build stronger communities through affordable home loans

Soup is a non-profit working with low income homeowners