According to the 1990 census, only around 1% of all homes in the U.S. lacked a complete set of plumbing facilities, down from 45% in 1950. But a new report claims that recent rashes of thievery have resulted in significantly more homes without proper plumbing.

Bloomberg reports that, as of 2011, the percentage of U.S. homes without complete plumbing systems had jumped up to 2.2% (around 3 million homes), more than double what it had been 20 years earlier. Between 2008 and 2011, that number increased by 10.4%.

The census says a home must have hot and cold running water, a flush toilet, a bathtub or shower, and a sink with a faucet to be counted as having a full plumbing system.

Among the larger cities with increases in homes with missing pipes and fixtures are Detroit, Flint, MI, Cleveland, Dayton, OH, Camden, NJ, and Buffalo.

Detroit has the most homes — around 68,000, 19% of all units — without the proper plumbing, but Gary, IN, has the highest percentage rate of U.S. cities, with 24% of homes lacking complete plumping.

The increases in plumbing-less homes are tied directly to scavengers attempting to profit of the metal pieces they can pull out of empty homes and re-sell to scrap yards.

“When a unit becomes vacant in large parts of Detroit, Cleveland, Camden, you name it, it gets stripped,” explains Alan Mallach from the Brookings Institution. “Where you have these roving stripping gangs, as well as vandalism, the houses will go pretty fast.”

The damage to these homes can make them even more worthless to potential buyers. Bloomberg points out that you can get a 3-bedroom home in Detroit with a full plumbing system for only $10,000. Strip those pipes out and you might as well just tear down and build something new.

One plumber in Camden warns customers that he installs above-ground pipes at the homeowners’ peril.

“I will sell you copper lines, but more likely I will take pictures, and I want it inspected the same day because the great chances are that tomorrow it won’t be here,” he tells Bloomberg.

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