In the context of the housing market throughout the United States in recent years, many homeowners have taken to building additional structures on their properties to make room for family members or renters to live comfortably alongside them.
This trend encompasses many different names for the types of residences that people have been building. Some people have called these additional structures guest houses, but in many legal codes they are referred to as ADUs, or accessory dwelling units. Is this difference in terminology just a matter of preference, or are we talking about different things?
What is the difference between an ADU and a Guest House?
Some of the defining characteristics of what makes a guest house a guest house would not apply to an accessory dwelling unit. ADUs include their own kitchens, making them more fully independent living spaces from the main house on the property, but guest houses do not.
In some cases, to be considered an ADU, the structure must have a full kitchen, and it must also have a full bathroom. A guest house cannot have a kitchen, and it only has to have the bare minimum of bathroom facilities. It’s essentially just enough to be a private space for sleeping.
There’s also a subset of accessory dwelling units, the junior, or JADU variety, which can sometimes fall in between these requirements. Most of the time, though, these Junior units are much smaller. They’re generally formed by subdividing a portion of the original property, whether by adding an access door from outside to an existing bedroom, or converting a garage into an outdoor-accessible living space.
One of the other sharp distinctions is that a guest house must always be a detached and permanent construction. ADUs have the option of being either attached to the main house, being built as an addition to the original structure, or being a separate structure. For an ADU, this can include the possibility of building a tiny house or other such small structure for permanent placement on a property.
To qualify as an ADU, the residence either has to have a full bathroom, as mentioned before, or have a way to directly access a bathroom, whether it’s within the unit itself or within the main house, if it is to qualify as a JADU.
Homeowners building a guesthouse have the option of deciding whether they want to give it a full bathroom, or just a half bath.
What is a guest house?
If you have a second residence on your property, and it’s not meant for occupancy by long-term renters, and does not have a kitchen, then that is a guest house. The idea with guest houses, and hence the name, is that they are a temporary residence for guests of the property owner.
Guests are allowed to stay in and pay for their time in a guest house for short periods of time. Many guest houses can be used as vacation rentals, given the proper permitting. They are sometimes considered to be a step higher than a typical bed and breakfast, but not quite a hotel.
The fact, however, that they do not come with their own kitchen, or even a wet bar in some places, ensures that they will be dependent on the main property for some amenities.
Guest houses are allowed to have their own half or full bathrooms, but that’s about it. Most localities will permit them to be built in more zones, including rural or agricultural areas, than would otherwise be permitted for an accessory dwelling unit or any other type of additional structure on the property.
In some jurisdictions, guest houses are also defined by a strict upper limit on their square footage. This limit will vary depending on the locality.
Laws regarding ADUs and guest houses
Naturally, different jurisdictions in different states throughout the country are going to have different laws and requirements regarding these types of housing.
There are variations across each of these jurisdictions, but the basic principles remain the same. A guest house is always a separate, detached structure, where it’s defined by law, and accessory dwelling units are suitable for long-term rental, while guest houses are not.
Guest houses don’t have kitchens, but the other units can and do. Guest houses can be used for short-term vacation rentals, and the other units cannot.
So let’s take a look at some of the specific requirements for these different types of structures in the major cities of the West Coast.
Los Angeles ADU and Guest House laws
At the beginning of 2020, new laws came into effect in California which superseded all of the previous local zoning ordinances that affected accessory dwelling units. Some of these laws may have also affected the requirements for guest houses specifically as well.
The result of these changes is that information on these specific laws that currently apply is difficult to find on city webpages. The city of Los Angeles does have an information page that showcases the cities desire to strongly incentivize the construction of these types of residences. Most other information that can be found online concerning them is now obsolete.
Los Angeles County does also provide some additional information specifically on ADUs. This page explains the following:
“An Accessory Dwelling Unit, also known as a granny or in-law unit, is a living unit that may be up to 1200 sq. ft. An ADU is an attached or detached residential dwelling unit which provides independent living facilities for one or more persons. The ADU unit is located on the same property as the primary residence, and is accessory to the primary residential building.”
“An ADU is required to provide permanent provisions for living, sleeping, eating, cooking facilities, and sanitation, as well as, meet other requirements as stipulated by applicable life and safety code requirements from the Department of Public Works, Building and Safety Division and Fire Departments.”
Since Los Angeles itself is surrounded by more than 90 suburb cities spread across five counties, it’s very important to carefully research the requirements of the specific jurisdiction that your property falls within.
San Francisco ADU and Guest House laws
The San Francisco Bay area suffers from similar conditions to Southern California, such that there is a severe housing shortage that has made the construction of these types of units strongly incentivized.
Being also part of California, San Francisco and its suburbs are also in the same situation regarding the new laws that were passed at the beginning of 2020. The local ordinances no longer apply, and the state codes are what matters now, but most city governments in the region are sharing their specific adaptations of those laws on their individual websites, as they become available.
Not all localities currently have regulations in place that make distinctions between accessory dwelling units and guest houses. One of those that does is Sonoma County, a popular tiny home destination in the wine country north of the Bay Area.
The Sonoma County planning website provides a detailed breakdown of what makes each of those types of units different.
Seattle ADU and Guest House laws
The City of Seattle likewise does not have an immediately recognizable distinction between accessory dwelling units and guest houses. What they do have, however, are resources that explain in considerable detail the process of planning and beginning construction of a backyard cottage, as they call them.
Portland ADU and Guest House laws
Many of the City of Portland, Oregon’s laws on accessory dwelling units and other structures similar to guest houses can be found from this portal.
In particular, this city specifies the name for guest house-type structures as “accessory short term rentals.” Their website has a list of frequently asked questions regarding how to manage them.
One of those FAQs give us some indication as to what types of structures are permitted to serve as short term rentals, but they tend to refer mostly to a certain number of bedrooms in the existing main structure on the property.
An Evolving Market
Especially in the context of California’s new laws, the market for accessory dwelling units and guest houses is currently in a state of flux. It might be a few years before things settle down and the specific requirements for each of these types of residential structures becomes easier to pin down.
The key Takeaway, though, is that there is a market for these types of constructions. Each of these cities suffers from housing shortages, due to high demand and geographically constrained supply. They all need the benefits of additional residential units that can be built quickly and easily.
California cities are paving the way, thanks to the state’s new laws. It’s very likely that the rest of the West Coast will follow suit, and start making more housing available to more people, as well as offering travelers a greater flexibility through the use of guest houses.
Whether you simply need more space for your family, or you’re looking to create a new source of income, ADU use and guest houses are important options to consider. Just make sure that you research carefully the specific laws where you live!