Households use an average of 107,000 gallons of water a year, according to the U.S. Department of Energy. But installing water-efficient toilets alone will translate into a savings of 14,000 to17,000 gallons per year for a family of four, according to the Environmental Protection Agency. | Households use an average of 107,000 gallons of water a year, according to the U.S. Department of Energy. But installing water-efficient toilets alone will translate into a savings of 14,000 to17,000 gallons per year for a family of four, according to the Environmental Protection Agency. |