Question about water supply in DC and MD

I live in the DC area, which has recently been troubled by a new scandal of civic mis-mangement: apparently a number of houses are served by lead supply lines running from the main line in the street to the individual houses. Numerous residences have lead levels many times the reccommended limit, and although the DC sewer and water authority has known of the problem for some time, they have chosen to stay mum.

Anyway, I live in suburban Maryland, about a mile from the district border, and am served by a different water authority. This leads to my question: How does the split between suppliers manifest? Are DC and the surrounding suburbs completely distinct in their water lines? Are there simply no pipes crossing Eastern or Western avenuues, or is there some intermingling of supply? How about the sewage?

You are served by WSSC. According to their site,

And according to their lead fact sheet (warning: pdf):

WSSC also says they don’t have any lead mains or service lines.

Can you send me a few gallons?

Now you ask. I just poured 40 liters of seltzer down the drain yesterday evening.

Anyway, my question has to do with the interconectedness of various water supplies. In the case of power, for example, there is a high degree of connectivity between different service providers. If PEPCOs plants suddenly disappeared, I could still get power from a different part of the grid (in theory anyway, as the events of last year proved.) Is the same true of water and sewer providers? If I were to swim upstream through my supply pipes, could I get to the treatment plants of multiple providers?

Water is not nearly as interconnected as electricity. This makes sense, because since it has mass and also doesn’t travel at the speed of light, it’s a lot more difficult and more expensive to transport over long distances than electricity is. Large water providers have their own sources (such as resevoirs). In suburban areas with many political boundaries like ours, some providers may end up selling water to other municipalities who don’t have access to their own resevoir.

Despite living in Rockville, I don’t know where WSSC water comes from, but I’m pretty sure it’s somewhere in Maryland. In fact, I’d be unsurprised to learn that the heavily urban District buys water from Maryland, but maybe it gets enough from internal sources.