not sure I understand the question? I know at least a half dozen people who dig in DC.
You mean like the White House privy or something?? I assume it was a joke.
Guys who have dug in DC have concluded that the pits were very shallow and/or were likley drawer privys. I know of guys who have probed empty lots all day, dug test holes and found nothing. A large portion of the city lies within the Potomac River floodplain. Due to wet soils and the concern for diseases they cleaned their privys frequently. There are pits in Georgetown and Alexandria, VA.
The bigger question is where did all of thet stuff from DC go? I've been told the area under the National Mall is landfill. If not there, it must have gone out in barges into the Potomac. There are no large DC dumps to speak of. Most of the smaller localized dumps have been covered up during construction. All but a few of the DC bottles I've found have come from construction sites that have exposed some trash feature. Unless you are able to travel the area on a regular basis to spot new construction, it's not worth the effort to look for pits. There may be some pits, but they are far and fer between. Hope that helped.
Could you explain "drawer privy"?
It would be one of those pieces of trivia that clogs my brain and pushes out all the stuff i am supposed to remember.