California ADU Law: What You Need to Know
Accessory dwelling units (ADUs), also known as granny flats or in-law suites, have become an increasingly popular option for adding living space in California. This article summarizes key details of California ADU Law, including recent changes, to help you understand the requirements, restrictions, and opportunities related to building an ADU.
California State first adopted laws specifically allowing and regulating ADUs in 1982. The original policy intent was allowing homeowners to create small homes within or adjacent to existing residential structures, providing more affordable housing options for family members, students, the elderly, in-home health care providers, renters and others. ADU laws have undergone numerous updates over the years, with the state legislature continuing to encourage ADU construction through various reforms.
Who Do California ADU Law Apply To?
California’s ADU laws allow homeowners to create a secondary dwelling unit on any residentially zoned property, whether in single-family or multi-family housing. This includes newly constructed homes as well as existing houses and condos. Specific requirements may vary by locality.
Key Provisions, Requirements, and Restrictions
California ADU law includes statewide standards and requirements, which local governments can then adapt and add to within certain parameters. Here are some of the key provisions:
Number of Units Allowed
- Lots zoned for single-family housing may have one attached ADU (extension or conversion of existing space) AND one detached ADU (stand-alone construction).
- Lots with existing multi-family dwellings of any kind may have up to 25% of their current units be ADUs, up to a maximum of two.
ADU Size Limits
- Attached ADUs are limited to 50% of the current living area or 850 square feet for a studio or 1 bedroom unit, or 1000 square feet for a 2+ bedroom unit, whichever is less. No size limit if the ADU is fully within existing primary dwelling space.
- Detached ADUs have an increased size limit of 850 square feet for studios and 1 bedroom units, or 1000 square feet for 2+ bedroom units statewide. Some localities restrict further.
Parking Requirements
- As of January 2023, off-street parking is NOT required in most cases when creating an ADU anywhere in California. Previously this only applied in transit-rich or walkable neighborhoods. Parking can still be required by some localities under special circumstances.
Setbacks
- No setback (the distance between structures and property lines) can be required for an ADU that is converted from an existing structure or a new structure in the same location. Some setbacks may apply for new detached backyard construction.
Fire Safety
- All ADUs must provide applicable life-safety protections like smoke alarms, carbon monoxide detectors, and fire extinguishers. Fire sprinklers may be required depending on the location and adjacency of structures.
Impact Fees
- Utilities connection fees or capacity charges can’t exceed the reasonable cost of providing service, must be proportional to the ADU’s burden based on its size and features compared to the primary home, and no extra fee can be charged for existing utility connections. Most impact fees related to schools, infrastructure, etc. are effectively waived currently.
Rent Control
- Local rent control policies do apply to ADUs occupied by tenants. Rent limits and tenant protections cannot be waived.
Sale or Conveyance
- ADUs cannot be sold or otherwise conveyed separately from the primary residence and lot in almost all cases. There are occasional exceptions where minimum lot size and setback rules are met.
60 Day Approval
- As of January 2023, California ADU permit applications must be approved or denied within 60 days. Previously jurisdictions had longer windows for review.
Penalties for Violating California ADU Law
Fines of up to $10,000 per violation per day may be imposed for failure to adhere to California’s state standards. Additionally, unpermitted construction can potentially result in the forced removal of the illegal unit.
Examples of violations include:
- Renting an ADU for less than 30 consecutive days (considered short-term/vacation rental)
- Operating a detached ADU as an entirely separate residential property instead of a secondary use
- Charging unlawfully high utility connection fees or hookup costs
- Refusing to approve compliant ADU permits within 60 days
- Requiring setbacks for conversions of existing structures
Fines would typically be levied against the property owner, but tenants could also be held responsible for improper use violations.
Recent Changes and Proposed Reforms
California’s ADU laws have seen over 10 notable updates in the past 5 years alone, with the state legislature consistently expanding options and incentives for ADU projects. Recent reforms include:
January 2023:
- 60-day approval mandate
- Parking no longer required in most cases
January 2022:
- Lot split option to sell detached ADUs
- Fire sprinkler exemption if the existing primary home lacks sprinklers
January 2020:
- Allowing ADUs and JADUs (Junior ADUs, typically converted bedrooms/bathrooms) on single lots
- Opening detached units and JADUs to be rented long-term instead of only used by family
- Lifting owner-occupancy requirements
The consistent pace of change has spurred a major wave of new ADU projects and has revealed additional challenges and undesirable barriers. As of late 2022, further reforms are already being proposed for 2023-2024 including revisiting lot split and conveyance restrictions, providing state financial incentives, and strengthening enforcement to prevent exploitation of tenants.
California ADU Law Controversies and Challenges
Increased ADU construction has not been without controversy. Common areas of criticism, debate and ongoing problems include:
Community Fit
- Detached backyard cottages raise privacy, noise, and density concerns as stable neighborhoods adapt
Inadequate Infrastructure
- More units straining already outdated electrical, sewer/septic, and parking systems
Insufficient Affordability
- New ADUs catering to wealthier rental markets vs. serving lower-income family needs
Permitting Delays
- Continued NIMBY obstruction and foot-dragging by local governments and planning agencies
Limited Accessibility
- ADUs still inadequately serve disabled and elderly populations needing single-floor and wheelchair-friendly housing
Design Conformity
- Cookie-cutter prefab options lacking aesthetic harmony with the surrounding architecture
Tenant Exploitation
- Lack of adequate enforcement mechanisms to prevent illegal overpricing and abuse of uninformed renters
Addressing these issues while still nurturing growth in ADU availability remains an ongoing challenge at all levels of governance as well as for community organizations.
California ADU Law Conclusion & Key Takeaways
ADU laws in California continue to evolve with the priority of maximizing housing opportunities throughout the state. Although adding an ADU involves meeting various legal requirements, the process has become significantly more feasible and affordable due to impact fee waivers, design flexibility, and approval reform.
Key takeaways about California’s ADU policies include:
- Allowing up to two accessory units on almost any residential property
- Fewer restrictions on unit size, parking, setbacks, and zoning
- 60-day approval mandates to limit obstruction and delays
- Most impact fees and hooks up charges are now waived
- Rent control does apply; short-term rentals still banned
- Detached units can now potentially be financed and sold separately
Hopefully, this summary has provided a helpful outline of the current state of California ADU laws and critical issues to consider. Be sure to consult your local zoning office to check if any specific requirements apply within your county, city, or homeowner association. With supportive policy frameworks now in place, adding an ADU can be a strategic opportunity to meet evolving housing needs and preferences.
