Water Wasted by a Dripping Faucet
According to EPA WaterSense, a faucet dripping about once per second can waste more than 3,000 U.S. gallons of water in a year. At that drip rate, the estimate is about 11,400 liters per year.
This is an illustrative estimate, not an exact amount for every faucet: drop size and flow depend on pressure, the aerator, worn seals, and faucet design. The USGS notes there is no single scientific standard volume for a faucet drip; measurements of household faucets found varying drop sizes.