Going grey

Cathryn Hickey, Executive Director for the National Skills Academy for Environmental Technologies, looks at where to start when it comes to greywater reuse.

Greywater refers to waste water that is discharged from wash basins, baths, showers and washing machines. This water can be reused for ‘non-wholesome outlets’ such as watering the garden, car washing and toilet flushing. Like harvested rainwater, greywater is classified as a Class 5 risk under the Water Supply (Water Fittings) Regulations 1999.
In some circumstances, it is possible to use greywater to supply a washing machine if it is appropriately treated. For irrigation, greywater should be directly applied to soil and not through a sprinkler or method that would allow contact with above ground portions of plants. Greywater should not be used to water crops, which are eaten uncooked. It is also recommended that greywater should not be applied to seedlings or young plants.
Greywater is not permitted for:
• Drinking water
• Dish-washing (hand or machine)
• Food preparation
• Personal washing
• Showering and bathing
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