Want to know an easy way to save a whopping one THOUSAND gallons of water a month? Just run your dishwasher and washing machine when you have a full load. To save another thousand gallons a month, cut your shower time to five minutes. And here's a quick way to see if you need to replace your shower head with water-efficient one: does your shower fill a one-gallon bucket with water in less than 20 seconds? If so, better change that head! A low-flow shower head can save 500 gallons of water a week.