Examples of upzoning in Brooklyn, New York. Upzoning is one of Seattle's strategies to increase the supply of affordable housing.
Upzoning is a convenient way to describe a zoning change that increases the density of housing within an existing residential zone.
There are a limited number of ways that urban areas can add new housing, whether market rate, or in some fashion deemed ‘affordable.’
New housing can be built on ‘lazy land’ — land which has fallen into disuse, or is being held privately without active development plans. ‘Brownfields’ are disused industrial land, which may need remediation to remove pollutants in the soil. As well, brownfields may require servicing with roads, water and sewers.
New housing can be built on the outskirts of a city, swallowing up green space and farmland. This kind of development adds to road traffic congestion, or requires expensive transit systems to connect the housing to work and shopping.
One of the simplest ways of adding new housing to a city is to allow increased density development in low density neighborhoods by upzoning.
The least obtrusive kind of upzoning allows development within an existing building — a basement flat, for example. Slightly more obtrusive are small homes added in low density residiential districts — a little cottage at the bottom of the garden, for example.
More obtrusive still (at least in the eyes of neighbours) are low-rise apartments, condos and townhouses. These may be built to the same existing height restrictions of the neighborhood and therefore have a relatively small aesthetic impact.
Upzoning that allows medium- and high rises in a neighbourhood are the most dramatic, and most intrusive ways to increase housing density. Such rezoning proposals are usually vigourously opposed.
Regardless of the type of upzoning, there is usually some type of NIMBY (Not In My Back Yard) protest movement against rezoning proposals. The NIMBY objections range from the catch-all ‘changes the character of the neighborhood’ through ‘creates traffic problems’, ‘creates parking problems’, ‘increases local crime’, and more. Depending upon the jurisdiction, such protests can spawn legal challenges which tie up up proposals for months or years.
For an example of an urban upzoning proposal, as well as the kinds of hoops an urban area may have to jump through to successfully rezone, read more in the Seattle Times: Ruling mostly clears Seattle’s plan to upzone neighborhoods for affordable housing