NHEH Publications

Accessory Dwelling Units are Easier than Ever to Build

By Anne Secker, Attorney
Noland, Hamerly, Etienne & Hoss


As of January 1, 2020, granny units and backyard cottages are easier than ever to build.  These structures are technically known as Accessory Dwelling Units (“ADUs”), which are secondary residential units built in backyards of lots containing an existing single or multi-family home.  California lawmakers loosened up restrictions on ADUs again in 2019 by enacting SB 13, AB 68, AB 587, and AB 671, with the hope ADUs will increase the amount of housing available to Californians.  These laws follow on the heels of other laws adopted over the past 4 years to make ADUs easier to build.

Some commentators criticize these laws as the “death of single family zoning in California” because now property owners can build up to 2 ADUs as a matter of right on their property.  Other commentators believe that ADUs are an important piece in solving the housing crisis because such units may offer an affordable solution to individuals who lack the means to pay for a more traditional housing.  This article outlines some of the changes these new laws make regarding construction of ADUs.

SB 13

SB 13 makes it easier and more affordable to build ADUs by removing costly requirements some local agencies have implemented including:

  • Prohibiting a local agency from requiring an owner to replace parking spaces if a garage, carport, or covered parking is removed to construct an ADU.
  • Prohibiting a local agency from requiring that an owner must occupy the property as a primary residence.
  • Shortening the deadline for review of ADU applications from 120 days to 60 days.
  • Prohibiting a local agency from imposing impact fees on ADU’s that are less than 750 square feet in size.

AB 68

AB 68 lets owners build up to two ADUs on their property.  Local agencies may not:

  • Impose any additional conditions on ADUs than what is already in the agency’s zoning code.
  • Require the lot on which the ADU will be built to be a certain minimum size;
  • Require an ADU to be attached to the primary residence.  ADUs now can be attached to a garage, storage area, or other structure on the property.
  • Require ADUs to be less than 16 feet in height or require rear and side yard setback to me more than 4-feet.

AB 587

Prior to AB 587, an owner was prohibited from selling their ADU separately from the primary residence with which it shared a lot.  AB 587 relaxes this law, allowing certain tax- exempt ADUs to be sold separately from the primary residence, so long as certain conditions are met.  These conditions include, among others:

  • The ADU be built or developed by a nonprofit corporation whose purpose is to build and rehabilitate residences to be sold inexpensively to low-income families.
  • A recorded contract exists that includes affordability restrictions on the further sale of the ADU to ensure that the property will remain as affordable, low-income housing.

AB 671

AB 671 incentivizes the construction of ADUs by:

  • Requiring local agencies to develop a plan to incentivize and promote the construction of affordable ADUs.
  • Requiring the creation of a list of state grants and financial incentives associated with planning and development of ADU’s with affordable rent.  This list must be posted on the website of the Department of Housing and Community Development by December 31, 2020.

Whether it makes sense for property owners to build ADUs on their property requires careful financial analysis.  Of course, additional considerations, such as privacy, parking and noise are also important considerations in deciding whether to build an ADU on your property.  If you like your current single family neighborhood the way it is, these new laws will make it harder to object to ADUs proposed by your neighbors.  Whatever your take on ADUs, we are likely see an increase in the development of ADUs in the years to come. 

© 2020 Noland, Hamerly, Etienne & Hoss