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Sewage and Plumbing Map of Washington, DC By Sarah Hank

by Prince Of Petworth August 14, 2012 at 10:30 am 37 Comments


To view a larger map please click here

The above map was made by Sarah Hank. She contributed a crime map of DC here.

Sarah writes:

So what was in that water that flooded Bloomingdale in July?

I started this map because I was routing through some census data and came across a weird attribute:  Housing with Incomplete Plumbing.  (Definition here)  I mapped it out, and did not see a real geographic pattern in the tracts that were affected.  It seems like group housing (The United States Soldiers and Airmen’s Home being the biggest example, hospitals possibly being another) has the most to do with places with higher percentages of incomplete plumbing. I’d be interested to see what readers think about this data!

I wanted to add something else related to “sanitary” matters to the map.  With all the flash flooding that happened earlier in the summer, I thought I’d highlight DC’s combined sewage system. I added in a layer showing the extent of the combined sewage system as well as Combined Sewage Overflow outfall locations. If you don’t know about DC’s combined sewage system, it basically means that in certain places in the city, rainfall run off and untreated sewage are combined in the same sewer.  That means that when it rains and the sewer becomes too full, the dirty toilet+rain water has to be released somewhere, namely the Potomac and Anacostia Rivers, and Rock Creek.  The minimum rainfall to trigger the outfalls is sometimes as low as 0.1 in, and at most 1.7 in. There are other outfalls in town, but I’m not totally sure how those work as I never see water flowing out onto the streets, say, at Q & 22nd NW.  Check out this informative guide from DC Water.  To be clear, DC Water does have a plan to convert the combined system into a separate system.  But for now, heed DC Water’s warning: “Please note that the District of Columbia Department of Health has imposed a ban on swimming in all rivers and creeks in the District of Columbia and any contact with rivers and creeks immediately downstream of any sewer pipe discharge should be avoided.”

Regarding concerns about flooding in Bloomingdale (which from the map, you can see is directly in the middle of the combined sewer area), DC Water has committed an entire page on their site to the issue.  Bloomingdale neighborhood residents who attended a special meeting by DC Water on August 4th would have seen this powerpoint.  I’m not going to claim to understand the situation fully, but it seems to me that the water that flooded the streets as well as numerous basements as a result of backed up sewers was likely the combined rainfall and sanitary waste water that I spoke about above. Raw sewage soup.

Do people know about this?  If there was really human waste in the flood water, why weren’t more people talking about it?

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