Short answer: YES! For a more detailed explanation, keep reading.
What Is An ADU (Accessory Dwelling Unit) Or JADU (Junior Accessory Dwelling Unit)
Accessory Dwelling Units, or ADUs are additional living quarters built alongside single-family homes that provide living facilities for one or more person independent of the original property structure. Colloquially known as granny flats, accessory dwellings, accessory apartments, or mother-in-law units, ADUs can be attached or detached to the main housing unit and have independent facilities for living, cooking, sleeping, dining and sanitation.
ADUs that are 500 square feet or smaller are classified as Junior Accessory Dwelling Units, or JADUs. The main difference between ADUs and JADUs, other than the size, is that the latter do not have their own bathrooms and share sanitation facilities with the main house. ADUs may or may not have an entrance-way separate from the main house, but JADUs are required to have an outside entrance.
Is Adding An ADU (Accessory Dwelling Unit) Or JADU Allowed in California?
Yes! Starting in 2015, California’s Legislature has passed multiple bills to encourage homeowners to construct of ADUs and JADUs by reducing local barriers to permitting. California is going through an extreme housing crisis, and lawmakers are exploring all possible avenues for quickly increasing housing supply. Accessory dwelling units are increasingly seen as an important way of providing affordable rental housing to college students or allowing elderly parents or people with disabilities to live closer to their families who can provide care and support.
What About HOAs and CC&Rs?
Many Home Owner Associations (HOAs) have been hostile to the idea of ADUs, placing restrictions on their construction in their Declaration of Covenants, Conditions, and Restrictions, commonly known as CC&Rs. A CC&R is a legal document that is part of the official real-estate records filed with county recorder’s office. CC&Rs give the HOAs legal authority to enforce and administer community rules of what the homeowners of that particular community can do with their properties.
To counteract the restrictions many HOAs have on ADUs, Assembly Bill No. 670 (AB-670) was signed into law by the governor in August 30, 2019. AB-670 unambiguously allows the construction of ADUs and JADUs in Planned Unit Developments (PUDs) and Common Interest Developments (CIDs). The bill even states that any HOA CC&Rs that prohibit the construction of and ADU or JADU is void and unenforceable if the construction takes place on a lot zoned for single-family use that meets the requirements of state law governing ADUs.
California law permits local governments to adopt limits for the minimum and maximum size of an attached or detached ADU, but those limits cannot be used an excuse to bar construction of at least one ADU or JADU. If an ADU requires a separate utility connection, the connection or capacity charge has to be in line with the size of the ADU or number of plumbing fixtures. Local governments also cannot require additional parking for an ADU if it is within one-half mile of public transit.
The Bottom Line
ADUs and JADUs are legal to build in single family homes in California. Unfortunately, many single-family homes are in developments/communities run by home owner associations whose rules make it difficult or impossible to construct an ADU or JADU. Bill 670 was designed to remove those barriers on the legal construction of ADUs/JADUs in a single-family home from local government or home owner associations.