For decades a lack of running water was mostly endemic to rural America. But it started to shift to cities in the 1990s with changes in the housing market, Meehan showed in a paper published in December in the journal Nature Cities. Low interest rates and an explosion in subprime lending pushed up home values and rents, curbing the stock of affordable housing. Low-income Americans, particularly those of color, were forced into more decrepit accommodations, while others fell behind on bills. The urbanization of plumbing poverty accelerated after the 2008 recession, and today 72% of US households lacking running water live in metropolitan areas, more than double the proportion from the early 1970s.