This month the first overhaul of DC's zoning rules since 1958 went into effect. The update, known as ZR16, aims to take a zoning code written during a different chapter in DC (and US) history and bring it into the modern era. ZR16 isn't a wholesale rewrite, but it does bring some important changes, both in terminology and in zoning rules, that will affect Capitol Hill. Here are some resources to help households understand the code and what it implies for your home and your neighborhood.
DC Urban Turf has a brief overview, along with a series of more in-depth articles. The Washington City Paper also had a nice, summary review. And here's a slideshow from the Office of Planning that walks through the changes in a bit more detail.
Some of the changes are mostly superficial, moving DC from zones like "R-4" to new names, like "RF-1" (RF = residential flat). Other common zones in Capitol Hill include MU-4 ("mixed use"), formerly C-2-A and MU-5-A (formerly C-2-B). The DC Office of Zoning has a conversion table here. (Hill East's special zones now range from H-1 to H-4.)
The old zoning map from the Office of Zoning was a great--if somewhat clunky--resource. This has been supplanted by two new maps. One provides an interactive feature to show how zone names have changed. The other, more useful in the long-run, is an updated zoning map for ZR16. The new map of course includes the new zone names, but it also brings a new and improved interface and easier to access information.
Major Changes Affecting Capitol Hill
The complete zoning changes are too numerous to review, but here are some highlights that affect Capitol Hill. There are some important changes that primarily serve to simplify the zoning relief process, such as setting a uniform lot coverage standard (60%), which means end-unit rowhouses are no longer held to an different (and arbitrary) standard. I won't go into detail on those types of changes, either. Each of the section titles links to a post by the Office of Planning that walks through the details.
Accessory Dwelling Units (ADU): An "ADU" is a fancy word for separate, livable space that is in addition to the main home on a property. For example, an apartment in a carriage house. ZR16 makes it much easier to add an additional dwelling unit to a lot in most Capitol Hill zones.
Alley lots: The 1958 zoning rules were severely restricted what could be done on lots that abutted alleys, something Capitol Hill has in abundance. ZR16 radically redefines what owners of alley lots can do. Essentially, any lot larger than 450 square feet is eligible for a single family resident, with minimal setback and expansive lot coverage allowances.
Corner stores: Corners stores used to dot the Capitol Hill landscape, but now they're rare. (Greater Greater Washington has a nice post on houses that used to be corner stores.) ZR16 won't change things dramatically, but it does modestly relax the restrictions on corner stores. Anyone looking to put in a new corner store will still have to meet an extensive set of restriction on lot location, store size, and what they can sell.
Parking requirements: For multi-family structures, ZR16 reduces the parking requirements to 1 space for every 3 units, which reduces the requirements in many cases. There are additional reductions if the building is close to a metro station or other mass transit line.
The information above provides a general sense of how the zoning regulations have changes, but the details are important. The most in-depth information is available on the Office of Zoning's site with the detailed regulations. These are full-on zoning documents and not for the timid, but they're not as impenetrable as they first seem. Most of the information Capitol Hill Residents need can be found in Subtitle E (the RF zones).