If you live in one of four major U.S. cities chances are you're letting the benefits of a ubiquitous natural resource go right down the drain instead of using it to cut down your water bill.
Toilet flushing is the biggest use of water in households in the United States and the United Kingdom, accounting for nearly one-third of potable water use. But there is no reason that clean, treated, municipal water needs to be used to flush a toilet -- rainwater could do the job just as well.
A new paper indicates it rains enough in Philadelphia, New York, Seattle and Chicago that if homeowners had a way to collect and store even just the rain falling on their roofs, they could flush their toilets often without having to use a drop of municipal water.