Install an Adjustable FlapperAn adjustable flapper give you control over the amount of water used to refill the tank. It can save up to three gallons of water with each flush and is simple to install. First, check that the flapper is compatible with your toilet model. Once installed, adjust the flapper to get the right amount of water needed to do the job.
Install a Tank BagYou may know about the old trick of placing a brick to the toilet tank to reduce the amount of water per flush. Unfortunately, a brick can erode over time, leaving damaging grit inside the tank that can wear out rubber and plastic parts. A better solution is to use a tank bag. You simply fill the bag with water and attach it to the toilet tank. By displacing water it will reduce the amount of water needed to refill the tank after each flush. Of course, the amount of water you save is equal to the amount of water you put in the bag, so experiment to find the right amount to effectively flush the toilet.
Install a Fill Cycle DiverterBecause the toilet bowl fills faster than the tank and the fill valve doesn't shut off until the tank is full, excess water is fed into the bowl. A fill cycle diverter can eliminate this waste, saving a half-gallon or more per fill, by diverting water back to the tank when the bowl is full.
TIP: Many utility companies offer water-saving devices to their customers for free, so be sure to check with your local utility company before purchasing a water saving device.