Analyzing D.C.’s Inclusionary Zoning

After years of wrangling between affordable housing advocates, policy wonks, and real estate interests, D.C. has finally adopted a commonly-used approach to creating affordable housing.

Known as “inclusionary zoning,” the policy requires developers include units reserved for low and moderate-income families when developing large residential projects. In exchange, developers are allowed to increase the density of the project to offset the cost of these affordable units. One of the most well-known programs in the country is run by Montgomery County, Maryland, which has a Moderately Priced Dwelling Unit Program that has created over 13,000 moderately priced units of housing since 1974. Inclusionary zoning policies create affordable units integrated into larger projects, without getting the government involved in owning property. For years, real estate interests have resisted such a policy in D.C., complaining as recently as last October such a policy constitutes a “development tax” and would depress development in the District.

The D.C. Office of Planning put together a very detailed presentation last fall to explain how the program would work. The following slides are from the presentation, however I suggest viewing the entire document via the link below. In D.C., the policy has been adopted in a way where it applies to roughly 37% of the city.

Inclusionary Zoning Map

Unlike Montgomery County, in D.C. the units must be reserved for qualifying individuals in perpetuity. Of the area where the policy applies, 19% falls within historic districts. Some have raised concerns suggesting the inclusionary zoning policy and the historic districts might conflict, however the Office of Planning points out that the historic districts contain few parcels large enough to trigger the inclusionary zoning law. They also point out that if they law was triggered, it would simply require narrower rowhomes, similar in size to many historic rowhomes in the city.

Inclusionary Zoning Area in Historic Districts

Here are a couple examples of how the law might work for projects in different zones:

Inclusionary Zoning - Changes to R-4 Zone

Inclusionary Zoning - Change to W-2

The D.C. Office of Planning estimated the program could create over 100 units of housing a year reserved for people below the area’s median income, currently around $90,000 for a family of four. However, because the enabling legislation only recently took effect, many of the specifics about how the program will be carried out (my understanding is that it will be the D.C. Housing Authority) remain unclear.


> DC Office of Planning Inclusionary Zoning Presentation (PDF) (10/07)
> W. Post: “Inclusionary Zoning Program Is Approved
> Washington Business Journal: “Mapping a disaster area: You are here” (7/14/06), “Affordable housing debate moves back, forward” (10/13/06)
> DC Council: Inclusionary Zoning Implementation Act of 2006
> DC Campaign for Mandatory Inclusionary Zoning
> Washington Regional Network: D.C. Campaign for Inclusionary Zoning
> Fall 2005 Student Report on Montomery County MPDU Law

Although I have done my best to be accurate in this post, it is based on my analysis of technical documentation of a complex, evolving policy. Anyone aware of inaccuracies should post a comment.

Author: Rob Goodspeed


  1. A “set down” means that is the area where the policy will apply, because it is being created only for specific zones.

Comments are closed.