An accessory dwelling unit is a really simple and old idea: having a second small dwelling right on the same grounds (or attached to) your regular single-family house, such as:
- an apartment over the garage
- a backyard cottage
- a basement apartment
Here are two examples, one above a garage and the other a small cottage.
Though accessory dwellings fell out of favor in the 60′s and 70′s, they’re coming back, and they have lots of names. Planners call them ADUs (Accessory Dwelling Units), but they’re also known as granny flats, in-law units, laneway houses, secondary dwelling units, and a hundred other names.
People build them for lots of reasons, but the most common are flexibility in housing and gaining income via rent.
Flexibility in housing makes sense for environmental, lifestyle, and financial reasons. Though many people buy houses and live in them for decades, their actual needs change over time. But the way that houses are currently built doesn’t reflect those changes, especially the way households may spend decades with just 1 or 2 members. Many American houses are too big for 1- or 2-person households, which is too bad, because size is probably the biggest single factor in the environmental impact of a house.
If you have a reasonably sized house, and an even more reasonably sized ADU, you’ve likely got a pretty green combination with some social benefits as well. You can have your best friend, your mother, or your grown kid, live with you. This kind of flexibility and informal support could really help as the nation’s population ages. Most people want to stay in their homes as they age, but finances and design can be problematic. An ADU could help aging people meet their needs without moving.
In many localities you can get legal rental income from a permitted ADU, or, if you want, you can live in the ADU and rent out the other dwelling. That should add a lot of flexibility to finances.
Despite all these likely benefits, ADUs are major construction projects. It isn’t always easy getting the design, financing, and permits arranged. That’s why we made this site. We hope it helps.