The increasing scarcity of affordable urban space and the demand for intimate, relaxed urban settings has led to an urban alley revitalization trend across many major U.S. cities. DC’s Height Act of 1899 limiting building heights to 110 feet has made space efficiency gains in the city that much more important.
As of September 2016, the following DC Zoning Commission changes affecting alleys went into effect:
- Alley dwellings will be permitted by-right in R-3, R-4 and R-5 zones in the city along 24-foot wide alleys, and on certain lots within 300 feet of a public street if the alley measures at least 15 feet wide;
- Single-family alley dwellings will also be allowed in other cases with a BZA special exception, pending input from DC Water, District Department of Transportation (DDOT), Department of Public Works (DPW), the local Advisory Neighborhood Committee, or other interested parties wherever applicable;
- Pre-existing alley lots must have a minimum square footage of 450 square feet in order for a dwelling to be built;
- Alley dwellings will also be subject to setback requirements and a height limit of 20 feet in residential zones. The height limit for alley dwellings in commercial zones will be 30 feet;
- In low-density residential zones (R-1 and R-2), alley dwellings will not be allowed;
- Multi-family alley dwellings could potentially be permitted in commercial zones, although they will remain prohibited in residential zones;
- Large alley lots can be split into more than one lot if square footage requirements are still met.