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You might have heard of a granny flat, an in-law enclave, or a backyard home. If yes, then you know what an ADU is. In a nutshell, in your area, an Accessory Dwelling Unit, or ADU, is a secondary, independent living unit built on the same premises as the primary residence. Generally, ADUs are constructed in one of the following four configurations:
Before planning an ADU, it’s probably a good idea to check with the relevant local authorities whether you’re permitted and eligible to build a secondary unit. Municipalities look at factors such as lot size and zoning laws to establish whether a homeowner can build an ADU.
As a first step, we recommend using our free Property Check to see your options.
* This is not meant, in any way, to replace speaking with your local planning authorities.
Ranging from detached ADUs that are half the size of the primary dwelling to a single bedroom, interior conversion ADUs, ADU construction costs naturally depend on the type and scope of the ADU you intend to build. That said, per-square-foot construction costs are usually the same for ADUs and new build residential structures. As such, your contractor or architect can probably give you a fair estimate once you’ve decided on your basic ADU plans.
Many, if not most, homeowners opt to fund their ADUs by borrowing against the equity of their homes. While home equity loans or lines of credit are the most common and straightforward form of financing, sometimes they aren’t practical or feasible. Such cases warrant more creative solutions, as in the following examples:
Whether any of the above or some other financing alternative, you should begin the process by speaking with the financial institution where you took out your home mortgage.
Public transportation is vital to many ADU tenants, especially if the ADU doesn’t come with permanent parking. Consequently, it’s probably a good idea to familiarize yourself with the nearby transit options to share this information with potential lessees. Most urban areas publish transit maps that include bus, subway, train, ride-sharing, and other information, making it easy to obtain the information you need.
In addition, check with your local authorities responsible for ADUs to see if there are any regulations regarding minimal distances to public transportation and to find out if you may be required to provide a parking space to your ADU tenant.
The short answer is no; you can’t sell your ADU independently of your home.
The ADU concept came about mainly to provide lower rent options in highly populated areas with insufficient housing and to allow homeowners to generate additional income from their existing properties. The very reason a municipality will give you a license to build an ADU in the first place is so that you can rent it out or use it for your own family. Therefore, the authorities only allow ADUs to sell with the primary residence.
You don’t have to live on your property and may rent out your primary home and your ADU.
Save, perhaps, for particular circumstances, most municipalities won’t allow you to convert a garage located in front of the primary residence. However, you should check with your city’s planning department to see if you might obtain a permit to construct some other form of ADU elsewhere on your property.
Please note that The ADU Guide provides information on new construction ADU units and does express any opinions on the current legal status of existing ADUs or propose to offer legal advice of any kind. With that said, some municipal authorities may allow you to legalize an unlicensed unit and reach out to your local planning authority to find out more.
As you might expect, the sizes of the various types of new-construction ADUs are regulated by local authorities and will likely differ from city to city. Here are a few general guidelines, but you SHOULD NOT rely on them and should check with your municipal planning department before commencing any construction:
In many areas, each lot is different from its neighbors; even where not, other homeowners have different visions for their properties and ADUs. For instance, you may be thinking of an above garage ADU, but building one would block the view of your home, such that a side attachment might be your better bet, or perhaps demolishing your garage and rebuilding it elsewhere on your lot with the ADU on top.
To help you decide, try to put your ideas down on paper and then discuss them with your planning authority.