If around two daily showers are taken at your house, you can grow a citrus tree.
Or, depending on how old your washing machine is, you can have a citrus tree if you wash between three to nine loads a week.
That’s how much water you use each year that you can use again to water a citrus tree. (For numbers crunchers: 17 gallons per shower or 20 to 50 gallons per laundry load divided into 9,000 gallons to water a citrus tree.)
Reusing water this way is called graywater — often spelled “greywater” — harvesting.
“It’s any water that’s been used once that is clean enough to use again,” explains Lincoln Perino, a project manager and designer for Watershed Management Group Inc. He’s responsible for teaching people about graywater harvesting and helping them design and install systems.