While many solutions and compromises have already been implemented, one of the most underrated solution to water conservation is the use of grey water. Grey water is the the relatively clean waste water from baths, sinks, washing machines, and other kitchen appliances. This water is not polluted with chemicals and can be easily cleaned. Obviously, grey water is not safe to drink and would not be used as an alternative to drinking water. However, grey water can be used as an alternative to water that we don’t ingest; such as for our toilet water (which accounts for a house holds biggest water usage) and for irrigation uses in your backyard. One misconception people often make about grey water is that it has come into contact with feces and other similar substances. In reality however, it is only the relatively clean waste water you use for laundry, or washing your hands. The water has never come into contact with feces or any other extremely dirty substance.
If we are able to unlock the potential benefits of grey water then we might just be able to take another step in the right direction. we would be able to save millions of gallons of water per year and continue to live our lives comfortably, knowing that our water isn’t running out
Source: http://greywateraction.org/contentabout-greywater-reuse/