WaterSense is partnership with EPA, which identifies products using water more efficiently without loss of performance.
Toilet uses most water: 26.7%; WaterSense toilet could save 4,000 gallons per year.
For a family of four, 3.5-gallon toilet uses over 23,000 gallons of water per year; 1.6-gallong toilet uses nearly 11,000; 1.28-gallon, WaterSense toilet uses less than 9,000 gallons.
Family of four flushes 20 times per day or 7,300 times per year.
Some new toilets can be installed without tools.