Dwight Merriam describes the important role accessory dwelling units can play in providing affordable housing.

You have probably heard of the term NIMBY, which is the acronym for “Not in My Back Yard.” It is the attitude of some people who are resistant to change and will oppose new developments that they fear will adversely affect them. Most of the NIMBY challenges arise out of attempts to increase residential density and to provide more affordable housing. The fear is that the loss of single-family zoning or the development of a more inclusive housing stock will change the character of existing neighborhoods. The NIMBY opposition is often couched in terms of adverse impacts on the value of existing properties, but the not-so-hidden agenda in many cases is one of class and racial exclusion. Single-family zoning is inherently exclusionary, as is redlining and racially-restrictive covenants (no longer enforceable, but other private restrictions requiring large, expensive homes are still with us).

In recent years, in addition to acknowledging the economic class and racist effects of planning and zoning, there has been an increasing realization that the households excluded through NIMBY opposition are often not all that different than those households who were able to purchase or rent homes in the past, but cannot now because of the lack of affordable housing and the increased cost of housing, both owner-occupied and rental.

Indeed, some of those who have been excluded include the children of families in those neighborhoods, children who are now grown up and want to live in those neighborhoods but can’t find affordable housing. Some of the excluded households include single-parents with their children. Among the excluded are empty-nesters, retirees, widows, and widowers.

Five years ago, households of single people in this country came to outnumber those with married couples. With the changing demographics in this country, including smaller and smaller household size, such that not too long from now, the predominant household type will be the single person, attitudes are changing. People are beginning to realize that something must be done to open up opportunities for all types of households and people in a wide range of economic means.


The fact is, in many of our developed communities with the housing stock dating back decades, that housing is now physically, functionally, and economically obsolescent. The single-family detached home in a large lot, designed and built many decades ago for the typical American household of the “Ozzie and Harriet” and “Father Knows Best” era, simply don’t fit the households of today.

This country is beginning to question what is called “single-family zoning.” There is a move afoot to allow denser, smaller units of housing, to be retrofitted in those neighborhoods of old.

This is the YIMBY movement, evidenced by the increasing acceptance of accessory dwelling units. They are sometimes called mother-in-law apartments or granny flats, but they are all accessory dwelling units (ADUs)

The American Planning Association describes the ADU as “a smaller, independent residential dwelling unit located on the same lot as a standalone (i.e., detached) single-family home.” They may be attached to the existing home, they might be developed within the existing home by carving up some of the space, or they may be part of a separate building, such as over the garage or as a freestanding unit placed in the rear yard.

The advantage of ADUs is that they capitalize on the existing infrastructure. No new land is required, and the utilities are readily accessible. The benefits include creating a smaller and more affordable unit for households that otherwise couldn’t find or afford housing. They provide an additional income stream for the owner of the existing house, and often they allow an older person to age in place by giving them an additional income stream and needed companionship and social interaction.

Some states, such as California and Vermont, have state laws that expressly enable the development of ADU’s. Vermont’s law provides: “Except for flood hazard and fluvial erosion area bylaws …, no bylaw shall have the effect of excluding as a permitted use one accessory dwelling unit that is located within or appurtenant to an owner-occupied single-family dwelling. An accessory dwelling unit means an efficiency or one-bedroom apartment that is clearly subordinate to a single-family dwelling, and has facilities and provisions for independent living, including sleeping, food preparation, and sanitation, provided there is compliance with [certain criteria].”

But the most astonishing and breakthrough developments in the YIMBY movement have come from Minneapolis and the state of Oregon.

The Minneapolis City Council late last year voted to amend its land-use plan to provide that every single-family lot may be developed as a matter of right, with up to three dwelling units. The effect of this change could be dramatic. It will likely bring into production a large number of new units, many of them affordable, and many of them sized for the households of today.

Bloomington, Indiana, is considering something similar, to allow up to four units on single-family lots.

Oregon is the first, and so far, the only state in the country, to similarly mandate as a matter of state law that lots in many areas may be developed as of right with two, three, and even four units, and in some instances, with “cottage clusters.”

Will these two landmark initiatives in Minneapolis and Oregon end single-family zoning as we know it? No. There will remain many exclusively single-family neighborhoods. But they will enable a denser and more appropriate housing stock to be developed and, presumably, make our neighborhoods more diverse and inclusive.

By: Tammy Campbell. October 31, 2019

Editor’s note: This article originally appeared on patch.com: https://patch.com/colorado/denver/great-yes-my-back-yard-yimby-revolution