Photo by Greg Rosenke on Unsplash
That quaint little cottage in your neighbor’s backyard offers more than just a respite from the hustle and bustle of life in the main house. It can be a sanctuary for temporary guests and for long-term residents alike, offering a place to call home without the price tag of home ownership. You may have seen these mini-escapes described as a “guest house” or an “accessory dwelling unit,” and while they share many traits, there are a few key differences that separate them. Here’s what you need to know before deciding which option is best for you.
They may look the same from the outside, but several important distinctions make ADUs and guest houses quite different from one another.
In the context of private homes in the United States, a guest house is a small dwelling on a property intended for guests to stay comfortably overnight in their own private area. They are separate dwellings from the main building on a property.
Guest houses typically consist of a bedroom, a bathroom, and may also have lounging or dining areas, depending on the guest house size and style. Guest houses typically do not have cooking facilities, but some may include a mini fridge and a microwave.
Short for Accessory Dwelling Unit, an ADU is a secondary housing unit designed to be separate from the primary residence on a property. There are several styles of ADUs, including detached ADUs (DADUs) that are entirely separate from the main residence, attached ADUs connected to the main residence, and a conversion that changes a garage, basement, or another unused part of a property into its own residence. Sometimes, you’ll see an ADU, and specifically a detached ADU, referred to as a backyard cottage.
An ADU is designed for long-term, everyday living, while a guest house is not.
The purpose of an ADU is to create accessible, affordable housing. They may be smaller than the average home, but they contain all the essentials for living space, including full bathroom facilities and a kitchen area with essential equipment like a fridge, stove, and sink.
From the onset, a guest house is designed for short-term stays. Akin to hotels, guest houses often do not have full kitchens. They’re also limited in use, as guest houses are only permitted for short-term stays, not permanent residency, by most regulatory bodies.
How you choose between building a guest house or an ADU comes down to how you want to use it, but there are some clear advantages to an ADU that can pay off in the long run.
Finally, before a shovel hits the ground, you need to make sure your ADU or guest house is fully compliant with the law. While ADU laws vary greatly from state to state, and even from one city to the next, the laws in these four popular cities can help you better understand what you can expect.
ADUs are permitted in any area of the city that’s zoned for residential use. If you want to build a detached ADU on your property, you’ll have to submit paperwork to the city’s Rent Board in addition to applying for a permit to add an ADU. If there are tenants on your property, they’ll have 30 days to formally object to the construction of an ADU on the property.
Notably, California recently implemented several state laws that make ADU building an easier process, overriding local law inhibiting ADU construction in the process. SB 1069 prohibits local governments from requiring ADUs to have their own utility hookups, and several laws regarding the building of ADUs, including the number of ADUs allowed on a single property, which is two. Notably, of the two allowed ADUs, one must be a Junior Accessory Dwelling Unit (JADU), which is less than 500 square feet, attached to the main home, and created by adding no more than 150 square feet to the property. The law also stipulates that local governments cannot supersede state law in matters regarding ADUs.
Just like in San Francisco, ADU construction in Los Angeles is governed by state law. However, the city does maintain some additional guidance to help property owners. These guidelines define items like access requirements, size requirements, height restrictions, and setback requirements. A detailed breakdown of ADU requirements in Los Angeles County can be found on the county government’s website. Additional information can be found on the City of Los Angeles’s website, which details permitting requirements and development standards, among other important information.
The city of Los Angeles also manages an ADU accelerator program which pairs older adults with property owners renting ADUs as a way to provide stable, affordable housing to aging individuals.
The city passed legislation in 2019 that eased the ADU construction process for Seattle property owners, including removing parking requirements, reducing the square footage of the minimum lot size, and defining a floor area limit. The city, which refers to ADUs as “backyard cottages” or “basement units,” manages an online resource containing preapproved DADU designs and a complete list of required permits and applications.
The city of Portland allows ADUs in areas already zoned for residential use. Similar to state law in California, Portland’s code was revised effective in 2021 to allow for more flexibility in planning, building, and obtaining permits for ADUs. Among the changes include the ability to build two ADUs on a single lot. The law’s changes also require wheelchair accessibility for new ADUs. If you’re exploring ADU options in Portland, the city has published a guide to the ADU permit process on its website.
ADUs allow for far more flexibility and use cases than guest houses. Intended for everyday living, ADUs can accommodate long-term stays, creating opportunities for both short-term and long-term rentals on your property. And through Spacial, you’ll have the right ADU partners on your side to plan and execute your project with ease.
With Spacial, the average time to completion is less than a year, and sometimes as quickly as four months. Our studio and one-bedroom ADUs in the San Francisco Bay Area are designed by a world-renown modular construction expert, so no detail is overlooked as you plan your ADU. And best of all, there’s no ragtag team of professionals to create – your dream team is all at Spacial, with one point of contact who guides you through your choices. We even handle the permitting process for you! So whether you plan to use your ADU as a guest house or rent it long-term, just sit back and relax while we take care of all the heavy lifting.
