Before the 1950s, toilets typically used 7 gallons or more for each flush. By the end of the 1960s, toilets were designed to flush with only 5.5 gallons, and in the 1980s the new toilets being installed were using only 3.5 gallons. Today, a new toilet uses no more than 1.6 gallons of water.

Not only does the tank size of your toilet contribute to how much water you use, but leaky toilets can consume up to 200 gallons per day! You can see some leaks as they trickle from the rim into the toilet bowl. You can hear the water running with some leaks, but other leaks are silent.
To check for silent leaks, remove the top of the tank and take out any colored cleaning agents. Flush the toilet so that the water in the tank is clear. Next, add leak detector fluid, dye tablets, or a few drops of food coloring to the water in the tank. If the tank is leaking, color will appear in the toilet bowl within thirty minutes.