 retrofitting your toilet retrofitting your toilet if purchasing a new toilet is not possible you can retrofit older models those that use 35 gpf or more in a couple of simple water saving ways  install a toilet tank bag  a toilet tank bag will save about 5 gallons per flush many water providers give them out to their customers for free or you can purchase one at most home improvement stores follow the enclosed installation instructions install a toilet fill cycle diverter  a fill cycle diverter will save about 5 gallons per flush it takes some toilets longer to fill their tanks than their bowls resulting in excess bowl water going down the drain as the tank continues to fill the fill cycle diverter is a simple plastic device that directs more water to the tank and less to the bowl during the refill so that both the tank and the bowl finish filling at the same time many water providers give them out to their customers for free or you can purchase one at most home improvement stores follow the enclosed installation instructions watch a video   indoor  