Grey water

Grey water is all wastewater that is discharged from a house, excluding blackwater (toilet water). This includes water from showers, bathtubs, sinks, kitchen, dishwashers, laundry tubs, and washing machines.

It commonly contains soap, shampoo, toothpaste, food scraps, cooking oils, detergents and hair. Greywater makes up the largest proportion of the total wastewater flow from households in terms of volume. Typically, 50-80% of the household wastewater is greywater. If a composting toilet is also used, then 100% of the household wastewater is greywater.

Not all greywater is equally "grey". Kitchen sink water laden with food solids and laundry water used to wash diapers are more heavily contaminated than greywater from showers and bathroom sinks. Therefore, different greywater flows may require different treatment methods that would render the water suitable for reuse.

Video - Greywater Recycling in Germany
by CWC partner fbr – produced within the The ZER0-m Project (Euro-Mediterranean Regional Programme For Local Water Management)

The presentation about grey water unfolds the way of use and reuse of water in households, makes clear all the requirements in the utilization of grey water and provides practical knowledge.