Along with news on population growth and increasing housing prices, we often hear the concern that the small footprint of the city is an impediment to growth. The discussions on height limitations in the city, work done by the Urban Institute and by our good friends at the Office of Planning made us think: How much vacant land is there in the District that can one day be developed?
We searched the District’s real property tax database for empty, unbuilt land. Of course, not all of this land is immediately buildable. Zoning and ownership factors greatly affect allowable development on these lands. And some of this land might never be buildable (Parks, rail tracks, other bits of land–do we want to see buildings in the Arboretum?). So think of this as an exercise over 300 years where population growth might make our current preferences less relevant.
Here is what we found:
- The District has approximately 300 million square feet of vacant, unimproved land. This accounts for about 19 percent of all land in the District’s real property tax database.
- Of this vacant land, only 14 percent (42 million square feet) is in the hands of private entities and individuals. These would be the simplest to build on (barring zoning limitations). Privately owned lots are concentrated in zip codes 20017 through 20020 and in 20002.
- Non-profit, non-taxable entities such as hospitals, universities, and churches own another 24 million square feet. Of course, we have seen many examples of such land being converted into mixed use. But, it takes a bit more time to get there.
- The District owns 34 million square feet, some by the District’s Housing Authority. These lands could be transformed into housing or mixed use, but the development must follow government procedures. It takes time.
- The United States government owns 197 million square feet of land (or 66 percent of the vacant and unimproved land). Of this, 133 million square feet are east of the river.
- In zip code 20032 (Washington Heights and Bellevue neighborhoods) only, the District and the U.S. governments combined hold 53 million square feet of land.
What does this all mean? The Office of Planning estimates, under plausible conditions, the District could add 175,000 new households by 2040. This would mean an increase in demand for over 200 million square feet of housing to house the new residents (see pages 27 and 28 here).
Twenty five years is not a very long time, so if we limit our new construction to privately owned vacant land only, to meet the 200 million mark, we would have to see a floor-area-ratio of 4 or greater–that is the usable construction area is four times or grater than the size of the lot. This is pretty dense. But of course there are other sources of land including parking lots, older buildings or properties with underutilized capacity.
Here is a map of all vacant land in the District by zip codes by ownership and tax status. We made interactive maps, too, which you can get to using the link here or clicking on the map below.
What exactly is this data? The data captures all lots and squares marked as vacant in the District’s real property database classified as commercial or residential. We eliminated smaller lots unless they are in the same square and combined made 2500 sq. ft. of land or more. The zip code results might be influenced by where ownership records fall within large properties.