Accessory Dwelling Units: What You Need to Know
An accessory dwelling unit (ADU) — also commonly referred to as a granny flat, guest house, or in-law suite — is an independent living facility that can be either attached to or detached from a primary residence. Hubbell & Hubbell Architects, Inc. offers architectural services for property owners in California who are considering adding one of these units to their property.
It's worth noting that an ADU cannot be sold separately from the main home, but it can be rented out. This makes it a practical option for housing long-term tenants, weekend guests, family members, or college-aged children who need their own space while staying close to home.
California ADU Regulations to Be Aware Of
If you're thinking about building a granny flat or backyard cottage, there are several regulatory updates in California that are relevant:
- Local governments are no longer permitted to prohibit ADU construction.
- A separate utility connection is not required if the unit is within an existing residence.
- The ADU will be zoned for single-family residential use if it has exterior access and complies with fire code, including side and rear setbacks.
- The floor area cannot exceed 1,200 square feet and must remain under 50% of the existing living space.
Regarding parking, one space per bedroom is generally required. However, exceptions apply in the following situations:
- Public transit is located within a half mile
- The property is in a historic district
- The ADU is part of an existing accessory structure or primary residence
- The occupant is not offered on-street parking permits where they are otherwise required
- The property is within one block of a car share space
Design Options and Practical Considerations
One of the practical aspects of an accessory dwelling unit is its design flexibility. A granny flat can include a kitchen, living area, and bathroom, and can be situated in a variety of locations on a property, such as:
- An attic
- A basement
- A garage conversion
- Above the garage
- As a fully detached, independent unit
Hubbell & Hubbell Architects, Inc. works with clients to design ADUs that suit their specific goals — whether that's generating rental income from a long-term tenant, accommodating visiting family and friends, or providing a semi-independent living space for a family member while preserving privacy for both parties.
Beyond the immediate use, adding an ADU to a property can increase its overall value over time. The unit offers flexibility in how a property is used without requiring a major overhaul of the existing home. Hubbell & Hubbell Architects, Inc. has experience designing a range of ADU projects and offers consultations for those interested in exploring this option for their property.
