Definition of black water in US English:

black water


  • Waste water from toilets.

    Compare with gray water
    • ‘After consumption, about 80 per cent of the water comes out as waste and this includes black water and grey water.’
    • ‘The sludge disaster was the nation's worst-ever black water spill.’
    • ‘Another plan used grey and black water output to construct a wetland.’
    • ‘You can use water - not your drinking water, but gray water, or water that has been used before but is not yet dirtied to the point of black water.’