Grist’s Umbra Fisk (the website’s point person for green living questions) recently revisited the toilet issue and doled out some very important water-saving tips: sink a half-gallon of water in the tank of your old toilet to stop it from using three gallons per flush, use the food coloring trick to test for leaks, and so on. What she left out were some important numbers on toilet leakage – numbers so big that they might inspire even the most skeptical environmentalists to take action.

Flush this:  20% of toilets in the US (that’s 267 million) are leaking at any given time. If there are five apartments in your building, you or one of your neighbors almost certainly has a leaky toilet, and that leaky toilet is wasting 100 gallons of water each day. All these millions of incontinent toilets add up quickly to an estimated 5 billion gallons wasted per day.  Not to mention the money we're flushing down the tank with all that water.

If you don’t trust yourself to remember to do the food coloring leak test on your throne now and again, but want a leak-free relationship with your pluming, another option is an automated leak alert thingy that was put on the market last year. Just slap it onto the outside of your toilet – it’ll detect leaks by measuring when the “vibration signature of your toilet’s flush” is off-kilter, and light up to let you know when there’s a problem.