EarthThreat suggests that the next time you are at a party, hack your host's toilet by lifting the tank lid and bending the rod connected to the float so that the float is a little lower, shutting off the water a little earlier. "Think about all of the water that could be saved with this trick. Toilets get flushed a hell of a lot. If one gallon of water is saved per flush, and that toilet is flushed six times a day, you will be responsible for saving over 2,000 gallons of water per year. Abuse five of your friend’s toilets and you will save close to 11,000 gallons with a six flush daily average."
Um, maybe not.
First of all, as one commenter pointed out, the float arm is screwed into a socket so if you bend it, the water pressure on the float ball will probably cause it to rotate so that it is bent up, raising the water level, possibly high enough that it will stay running and flow down the overflow tube, wasting thousands of gallons of water.
Secondly, in many modern toilets, the arm is plastic and won't bend. A much better hack is to carry a screwdriver and adjust the arm position. But wait, there's more.
Thirdly, modern toilets are designed to use only 1.6 gallons of water and some models don't work that well to start with. Cut the water volume down and people will start double flushing to compensate.
Fourthly, the math has got to be wrong. " If one gallon of water is saved per flush" then the toilet isn't going to work, that is two thirds of the water volume in a modern toilet, or in a pre-1994 toilet, almost a third of the water.
Fifthly, our measurements of a tank's inside dimensions of 7" by 14" would yield only 98 cubic inches of water; a gallon contains 231 cubic inches, so you would have to drop the water level two and a half inches to save a gallon of water and the arm would probably break if you tried to do that.
So in summary, stick to your own bowl and don't abuse your friend's toilet; it is probably counterproductive and doesn't save as much water as it is purported to.::Rethos Thanks anyways, tipster Graham!