Mythbusting The Accessory Dwelling Unit



I see there has been some concern about “granny flats,” aka “accessory dwelling units,” aka casitas: these are little housing units homeowners can add to their property to help a parent age in place, or to rent out to someone in need of affordable housing. (Two common uses.) I can understand people are worried about the impacts on their neighborhood. I’d like to dispel a few myths about these valuable housing resources.

Myth: ADUs are eyesores. Reality: Most ADUs are converted garages or backyard units not visible to passersby. People constructing them want to rent them, which means they need to make them nice-looking. There’s a whole ADU movement, which means lots of design resources for those interested in building them. Here are some examples of ADU design. And here’s another page with examples of ADU design.

Myth: ADUs cause parking problems: Reality: There is no evidence ADUs cause parking problems. Most of those who use ADUs have fewer cars than people using larger, more land-intensive housing. ADUs tend to be dispersed, which is one of their great advantages, so their impact on any particular neighborhood is negligible. More reading:

Myth: ADUs will bring an “unwanted element” into the neighborhood. Reality: Diversity is good! Most single-family-residence zoned neighborhoods are white and wealthy, especially due to our nation’s history of redlining. ADUs are a fantastic way to bring diversity into a de-facto segregated neighborhood, and this diversity benefits everyone.

Myth: ADUs are radical infill. Reality: ADUs are a gentle way to add density to a city, dispersing new people over a wider range of land than a single large apartment unit. (Not that there isn’t a place for those, too!)

Myth: ADUs only benefit the middle-aged and middle-class. Reality: ADUs benefit a wide swath of people, from recent college graduates to retirees looking to age in place, which is why the American Association of Retired Persons (AARP) “supports the wider availability of accessory dwelling units, or ADUs, as an affordable, accessible housing option for people of all ages.”

Myth: ADUs aren’t allowed in single-family residential zoning. Reality: Yes they are. That’s why they’re called “accessory units.” Many cities and counties, including ours, permit ADUs in single-family zoning districts by right, subject of course to use-specific standards. What’s being proposed in the code update isn’t anything that hasn’t been vetted in the courts, and that isn’t already successfully being used in other municipalities.

Myth: ADUs will bring construction nuisances to your neighborhood. Reality: Many ADUs are modular, built off-site. Those built in the backyard won’t bring more noise than any other home remodeling project. And, there really won’t be very many of them in a given neighborhood—in cities that have made much more permissive rules about ADUs, the number built in a particular place hasn’t bumped up much; they are scattered around and residents don’t really notice them. In Denver, which recently overhauled its code to encourage ADUs, only 33 ADU permits are issued per year on average. For context, Denver is a city of 715 million.

Myth: Homeowners have a right to their neighborhood being exactly the way it was when they bought their house, and ADUs interfere with that right. Reality: Neighborhoods change over time. There are some neighborhood protections in place, of course, but nobody is guaranteed to have their neighborhood frozen in time. My neighborhood was very different 7 years ago when we bought our house: back then it was much whiter, much more uniform, much older. Many home sales later, it’s turned into a diverse neighborhood, full of kids, people from all over the world, grandfathers pushing prams up and down the street. My rights have not been violated by this change. In fact, it has added much vitality and life to our streets!

Myth: Los Alamos doesn’t want ADUs! Reality: A few people in Los Alamos are nervous about ADUs and want more information. Other people are excited to build them. The will of the town writ large is reflected in the Comprehensive Plan, which has named the lack of housing as one of the county’s biggest challenges, and has deemed the creation of housing to be one of its top priorities. Further, the Los Alamos 2019 Housing Market Needs Analysis specifically favors increasing ADUs: “Accessory dwelling units,higher density development,and expedited approval processes are examples of features that could be encouraged through the code rewrite. Accessory dwelling units are allowed in the North Community zoning district on single family lots of 6,500 square feet or more. Accessory dwelling units are an infill strategy that can accommodate needs in Los Alamos County, including student housing and multi-generational households. The development code should allow these units in more locations with clear requirements and conditions under which accessory units are allowed.” [Emphasis mine.]

Want more? Here are further resources:

Understanding ADUs by Planetizen Courses, a respected urban planning resource our county uses:

ADUs: what they are and why people build them:

AARP’s model ADU ordinances:

The White House encourages ADU development:

Still No Place to Live: The local barriers to the accessory dwelling unit revolution:

Five misconceptions about ADUs:

Why The Angst over ADUs?

ADUs ruin neighborhoods, and other myths: