Graywater is the water that goes down the drains from your washing machine, bathroom sinks and showers. When you stop to think about it, the average top-loading washing machine will use between 25 and 35 gallons of water per load. Just multipl[y] that out by how many loads you do a week, and then a month, which you can see will quickly add up to big numbers. Now imagine your shower and how many gallons that is.
A lot of wasted water that is going down the drain.