One of the most important trends in urban planning and development right now is the crisis that has resulted from high housing costs. This trend has been particularly damaging to the densely packed cities of the west coast of the United States. Cities like Los Angeles, San Francisco, Seattle, and to a lesser degree Portland, are all suffering from a housing crunch that has resulted in skyrocketing real estate prices, because they can’t build enough new housing to meet demand.
A new construction trend has appeared to offset those high prices, though. Many homeowners in suburban areas of these cities have backyards with enough room to build additional living space. In the past, homeowners would often build additions to their existing houses. Unfortunately that doesn’t solve the problem of making room for more families.
Now, though, thanks to years of advocacy, it has become far more cost-effective and convenient to simply plop down a separate, new structure on the same property, or to subdivide existing structures to create separate homes.
The backyard version of this strategy is referred to as building accessory dwelling units, or ADUs. These can come in many different shapes and sizes, and as they’ve gotten more popular, they’ve also gotten more specialized.
What is a Jadu?
A subset of ADUs that are smaller than 500 square feet in floor area, and which constitute part of a preexisting structure on the property are referred to as JADUs, meaning “junior” accessory dwelling units.
JADUs are an excellent solution for increasing the available housing stock even in more densely built, older suburban developments. They are thus an important way to make housing available for more people at lower cost. But why are they so necessary, and how do you define them?
We’ll take a look at some of the answers to these questions, but keep in mind that this article does not constitute legal advice. Check with your local planning authorities before beginning any modifications to your residential property!
Some Background on Why ADUs and JADUs are so Important
A big part of the reason for this new housing trend is that many of the big west coast cities are built in a region of constrained geography. Of the four, Portland has the most space to grow still, because it’s the smallest, and it’s built at the mouth of a large river valley, but the others are not so lucky.
Los Angeles, for example, is famously built on the coast, and it’s surrounded by towering mountain ranges that separate it from a vast desert. There’s no space left in the Los Angeles basin or the closest valleys surrounding it for large new cheap housing developments.
As the city grows outward, new construction requires extensive geotechnical engineering as homes are built on steeper and steeper hillsides, or new highways and other infrastructure have to be cut through mountain ranges to make the desert suburbs more accessible.
San Francisco is even more constrained than Los Angeles is. The city itself is built on the end of a peninsula, so except for the help of the city’s famous and very expensive bridges and tunnels, there’s only one direction it can grow on land, and that direction is also already built up.
All of the flatlands surrounding San Francisco Bay have now been fully urbanized, and the city is spilling inland through the surrounding narrow mountain passes to valleys further and further away. This causes horrifying traffic problems, in addition to making Bay Area housing absurdly expensive..
Seattle has a similar predicament, since the city is centered on an isthmus, with Puget Sound on one side and Lake Washington and the Cascade Mountains on the other. There is still some farmland surrounding the region, but the value of paving it over may not be so great in the long run. Most of Los Angeles’ famous citrus groves are gone forever, as are the Bay Area’s orchards. There are good reasons to preserve those land uses where they remain intact.
The result, though, in all of these cities, is that the only alternatives to increasingly difficult horizontal expansion are to build the existing urban area more densely. There are different ways to do this. One of them is to replace old housing developments with new apartment blocks and skyscrapers. But that’s a very expensive and time-consuming way to do it.
The other way is to fill in backyard spaces with ADUs, and supplement them with JADUs.
Characteristics of Junior Accessory Dwelling Units
The key characteristic of a JADU is that it is not a third structure on a property, but rather a subdivision of either the original house, or the ADU. It must be 500 square feet or less, and be entirely contained within an existing single-family residence, while still having its own, separate outdoor access.
It can be a garage converted into an apartment, or a specific bedroom within the house, as long as it is accessible from the outside as well as the inside.
Homeowners are allowed to add 150 square feet beyond their house’s existing footprint to create a JADU, but only for the purpose of making it more accessible to enter and exit the unit.
To qualify as a JADU, the dwelling must include a kitchen, but it does not necessarily have to have its own bathroom. JADU dwellers are permitted to rely on common sanitation with the adjacent structure.
ADUs and JADUs allow homeowners to alter the parking requirements that would normally apply to new residential units. With ADUs, you can sometimes eliminate parking, and in other circumstances, local governments are not allowed to require additional parking space. JADUs do not ever impose any additional parking requirements.
Another key difference between the two types of accessory dwelling units is that the standalone ADU is rentable, always. By contrast, the JADU can be restricted to owner occupancy. Local ordinances may require that either the JADU or the primary residence be owner occupied.
In jurisdictions that permit JADUs to be rented, though, that means that each single-family residential property is allowed to add two separate rentable units; an ADU and an attached JADU. Keep in mind that neither the ADU nor the JADU may be sold separately from the main residential property.
Laws Governing JADUs in California
Accessory dwelling units have been around for a few years now, but a monumental recent change in the industry that took effect at the beginning of 2020 was the result of two California state bills.
AB 68 and AB 881 have made it so that throughout California, single-family residential properties are now permitted to include both an ADU and a JADU. This basic provision, along with the code requirements that define what a JADU is, now applies everywhere throughout the state.
This new law is actually kind of a really big deal, because it has the potential to address multiple systemic problems that have been hurting California residents for decades.
These laws do still allow local municipalities, be they cities or counties, to establish their own ordinances governing JADUs. Chief among those potential modifications is the requirement that a JADU be owner occupied. There are other stipulations, though, such as the fact that local governments are not permitted to assess additional utility fees for a JADU.
Most importantly, the new law ensures that construction permit approvals for these types of units are now “ministerial” in nature, meaning that as long as the plans conform to essential construction, seismic, fire safety, and other basic codes, they must be approved.
We’ll take a look at some of the specific requirements for the four large cities we’ve discussed already, especially Los Angeles and San Francisco, since they are under the jurisdiction of these two assembly bills, but it’s important to keep in mind that even those two large cities form only a fraction of the urban area surrounding them.
What that means is that it’s very important for homeowners to be aware of the specific laws of the city or suburb that they actually live in. You can look up these laws with simple searches online, but make sure that you do!
Los Angeles
In some ways, Los Angeles was ahead of the game. Many of the provisions of the new California state ADU laws were already in place in L.A. before taking statewide effect. Some of L.A.’s codes ended up being more strict than the new state laws, though, so they were discarded until the city could devise new rules that conform to them. The same applied to the ordinances passed by Los Angeles County.
The main area you may have to watch out for with L.A.’s specific code requirements is that there are likely still restrictions for hillsides and other high fire hazard areas. Many other cities, especially in dry Southern California, likely have similar caveats.
San Francisco
As of this writing, the zoning codes for the City and County of San Francisco are in a transitional condition because of the new state laws. The link above directs interested homeowners to a two-page memo that outlines the city’s current understanding of the implications of the new laws, but the local ordinances are under review.
Anyone considering building an ADU or a JADU in San Francisco itself should be sure to work very carefully and closely with the Planning Department to ensure that they do so in a way that will be legal when all is said and done.
Laws Governing JADUS in Portland and Seattle
Portland
The codes governing accessory dwelling units in the city of Portland are in some ways more flexible than those of California, but in other ways more restrictive. They don’t currently make a distinction between standard ADUs and JADUs, and therefore operate under the requirement that all such living units have their own separate sanitation utilities.
They may be either attached to the house, or built as detached structures, though.
Seattle
Seattle’s municipal requirements for accessory dwelling units name the distinction between different types a little bit differently than the way California does. In Seattle, an accessory dwelling unit that is attached to the house such as a California style JADU, is referred to as an AADU, or attached accessory dwelling unit.
A standalone unit, by contrast, is referred to as a DADU. This refers to detached accessory dwelling units.
Seattle’s requirements impose some different restrictions as well. Only in certain zones of the city are two distinct units permitted. Low rise single-family zones generally only permit one.
Likewise, the square footage requirements can be somewhat different depending on the zone, and in fact, Seattle-area ADUs have a smaller maximum size whether attached or detached.
The Takeaway
Each of these major cities is currently experiencing a sort of renaissance in housing. All of them have suffered enormous growing pains over the past decade as populations have increased and housing costs have gone through the roof.
The rise of accessory dwelling units and JADUs represents an important way for the housing market to adapt to those conditions while making it easier for more people to find good places to live.