Should I worry about a leaking toilet? You betcha. If your toilet has a leak, you could be wasting about 200 gallons of water every day. That would be like flushing your toilet more than 50 times for no reason!
Older toilets use between 3.5 and 7 gallons of water per flush. However, WaterSense labeled toilets require 75 to 80 percent less water. They use 1.6 gallons and latest water saving toilets use 1.28 gallon per flush, this is 30% water savings
It takes a considerable amount of energy to deliver and treat the water you use every day. For example, letting your faucet run for five minutes uses about as much energy as letting a 60-watt light bulb run for 14 hours.
Heating water for bathing, shaving, cooking, and cleaning also requires a lot of energy. Homes with electric water heaters, for example, spend one-quarter of their electric bill just to heat water.
If your toilet flushes 3.5 gal / one person can consume as much as 19.5 gal or 7,135 gal /YR
If your toilet flushes 1.6 gal one person can consume as much as 10 gal or 3,760 gal/YR
If your toilet flushes 1.28 gal one person can consume as much as 6.4 gal or 2,336 gal /YR