Navigating Permitting for ADUs: A Simplified Guide

Feb 28, 2022

The prospect of adding an Accessory Dwelling Unit (ADU) to your property in California has become significantly more approachable thanks to recent legislative changes. Understanding the nuances between a Regular ADU and a Junior ADU, and the eased permit process, is crucial for homeowners considering this valuable addition. This article demystifies the process, highlighting the streamlined permit timeframe, reduced impact fees, and other essential considerations.

Understanding ADU Types: Regular vs. Junior ADU

  1. Regular ADU: Typically detached and up to 1200 sq. ft., these units offer independence and space, ideal for rental income or extended family.

  2. Junior ADU: Smaller in size, up to 500 sq. ft., and attached to the primary home. They feature a separate entrance, providing a balance of privacy and proximity.

Permit Timeframe Shortened

In a significant shift, cities in California must now approve ADU applications within 60 days; otherwise, the application is deemed approved. This expedited process is a game-changer, reducing wait times and uncertainty for homeowners.

Reduced Impact Fees for Smaller Units

For ADUs under 750 sq. ft., applicants can enjoy a waiver of impact fees. This exemption encourages smaller, more affordable units. Larger ADUs, however, may incur fees proportional to the size of the primary dwelling, but these are often significantly less than traditional construction fees.

Other Prohibited Restrictions on California ADUs

  • Owner Occupancy: There is no requirement for owners to reside in either the ADU or the primary residence.

  • Size and Setback Limits: Cities cannot prohibit an ADU up to 800 sq.ft. that meets a 4-foot side/rear setback and a 16-foot height limit.

  • Utility Connections: Separate sewer and water connections are not mandatory, offering cost savings as ADUs can share utilities with the main home.

  • Parking Requirements: If the ADU is within a half-mile radius of public transit, including bus stops, cities cannot mandate separate parking, easing the construction process.

ADUs on Single-Family and Multi-Family Lots

  • Single-Family Lots: These can accommodate both a junior and a detached ADU, maximizing the potential of the property.

  • Multi-Family Land: Up to two detached ADUs are permissible, offering a significant opportunity for property enhancement and value addition.


The eased regulations for ADU permits in California open a world of possibilities for homeowners. Whether it's for additional income, housing family members, or simply increasing property value, ADUs now present a more accessible and less cumbersome option. With these new guidelines, creating that extra space on your property is no longer a daunting prospect but an exciting opportunity to enhance your living situation and investment.