California ADU Ordinance 2020 – Most Important Laws Explained

ADUs are an increasingly popular way of elevating property value, creating additional housing space on a property, or adding additional functionality to a main building. Their growing popularity in California has led to legislative support in recent years, the most important of which is the set of ADU Ordinance Laws in 2020. 

A series of law revisions surrounding accessory dwelling units went into effect on January 1st 2020 in California. 

The revisions were meant to ease and regulate constructions of ADUs for property owners, investors, developers and construction companies, with one of the goals being to help reduce the housing shortage in the region.

Following the changes, it’s considerably easier to construct a new residential ADU, or convert an existing building into one suitable for use as a dwelling, thanks to Assembly Bills 881, 670, and 68, as well as Senate Bill 13. 

These bills have left many homeowners and investors with questions, so we prepared a list of the most important changes and explanations to help you fully interpret the new ordinance. 


Details of California ADU Ordinance Bills:

Starting with the Assembly Bill 881, a lot of ambiguities surrounding ADUs were cleared up, and minor improvements were introduced.


Details of Assembly Bill 881:

  • Compared to past regulations, with Bill 881 there are no longer minimum or maximum size requirements for an ADU based on the size of the main building. Previously, size limits were imposed as a percentage size ratio in relation to the main building. Size limits of 800 sq. ft. area, and 16 foot height still exist, but they are not tied to the size of the main building. 
  • ADU applications can be approved for mixed use zones, in addition to residential ones, giving both applications equal legal grounds. However, on an individual basis, municipalities can still regulate if an ADU is allowed on a mixed use zone. Also, permit applications must receive a legal response within 60 days, half the time limit of one that existed previously. 
  • From now on, the main building on the lot doesn’t require the owner to be the current occupant to rent the ADU. This change allows greater freedom for owners to rent or lease the ADU while they’re away.
  • If an ADUs is constructed on a parking area, or garages are converted to ADUs, there is no requirement for construction of additional parking spaces to replace the converted parking area. 
  • Setback and Height rules have been adjusted. ADUs require a front and rear 4 foot setback, and cant exceed 16 feet in height as mentioned above. These rules hold for a single story building, and buildings with multiple stories will depend heavily on local height limit laws. 
  • The legal term for ‘public transit’ is clarified to refer to bus stops and bus lanes within a half-mile walking radius of the ADU.


Assembly Bill 86 and Junior ADUs

Assembly Bill 86 focuses on a new ADU category, the junior accessory dwelling unit – Jr. ADU. This unit is categorized as a portion of the main building converted to serve a different purpose in practical terms, and with the new bill, it functions differently in legal ways too. 

The main structural factor that defines the Junior ADU is its connection to the main building. For example, a Junior ADU could be an attached garage that is converted into a studio unit. In total, this change allows for a total of 3 units on a single family lot. 


Here are the most important details of Bill 86:

  • Municipalities will be required to approve, in the case of a single family residence, an ADU and a Junior ADU up to 1200 sq. ft. and 500 sq. ft. respectively. Also in the same scenario, the ADU can be constructed on the footprint of an existing structure.
  • In a multi-family home scenario, multiple ADUs may be constructed, but only one ADU per four units.
  • In addition to a variety of other minor rules easing ADU construction, Junior ADUs don’t require additional parking if they don’t belong to the previously mentioned ‘public transit’ area.


Assembly Bill 870 and Senate Bill 13 Details

These bills pertain mostly to permits. In short, these are the biggest takeaways you need to know:

  • The legal body submitting an ADU permit does not have to be the owner or resident of the lot. This greatly helps companies like us handle the permit process in place of the client.
  • No deed or covenant may forbid the placement of an ADU on a single family lot. This extends to neighborhood groups as well, and they will no longer have power to prevent an ADU construction in the area. 
  • Agencies may not impose impact fees on ADUs under 750 sq. ft. in size, greatly benefiting developers.


What do California Ordinance Laws mean for homeowners and investors?

A sea of opportunity has opened up for construction of ADUs in California. If you were preparing to take steps in constructing an ADU, now is a perfect time. 

The permitting process has been greatly simplified and sped up, allowing you to fit the project in tighter development schedules. The financial aspects of ADUs have been greatly relaxed as well. Removing parking space requirements and size requirements gives owners greater budget flexibility. 

Finally, and most importantly, ADUs can now help the owner pay back their investment quicker. With the housing shortage on the market, affordable dwellings are sought after, and ADUs have never been easier to legally rent out. 

All of this is great news, but there will still be legal roadblocks on a case-by-case basis to constructing your ADUs. We recommend contacting a professional architectural company to handle the whole process for you, from obtaining a permit to the construction itself. 

If you want to further explore the ADU construction potential on your lot, or want to discuss a potential project, contact Yakov Build and get the most out of your property. 

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