SB9 vs. ADUs?

What is an ADU? An ADU is a small dwelling on the same grounds as, or attached to, a single-family house. It could be an apartment

over the garage, a basement apartment, or a stand-alone house in the backyard. An ADU may be used to house a family member or

for additional rental income.

What does Senate Bill-9 (SB9) provide? SB9 is a newly enacted California State law that became effective on January 1, 2022. The

intent of this bill is to address the mounting housing crisis in California. It allows for two different procedures in a residential area

zoned “single-family.” SB9 will allow up to 4 residences where only 1 was previously permitted.

• Splitting a lot into two parcels, which can be developed and/or sold independently.
• Conversion of a single-family house into a duplex, or by adding an additional single-family house to the same lot.

The development costs for both the SB9 and ADU options can significantly vary for design, permits, site work, right-of-way work, and

the structure’s allowed square feet. We recommend that the homeowner or developer perform research by contacting their

Municipality’s Planning and Building Departments to understand their development standards.

There are pros and cons to both the ADU and the SB9. The differences to consider can be different for either offering, and include

questions such as:

• Can you sell the dwelling units separately?
• Is an owner-occupancy required?
• What zoning is allowed?
• What about HOAs?
• Are impact fees waived?
• Are separate utility meters required?
• And many more questions!

There are many rules and regulations that the homeowner must review and understand. This is where Greenwood & Moore’s civil

engineering and land surveying team can help you! We can provide topographical and boundary surveys, tentative maps, grading

and draining plans, stormwater and utility requirements, ADA requirements, etc. We will be more than happy to talk you through

the differences.

If you have questions or require additional information, contact Greenwood & Moore.

Website References:

• California State ADU Information: Accessory Dwelling Units (ADUs) (ca.gov)
• California State SB9 Information: SB 9: The California HOME Act | Focus.
• Alameda County’s Overview Information: https://www.citystructure.com/blog/how-sb-9-applies-to-lots-in-alameda-county