How can grey water cause water pollution?

Grey water is domestic waste water that does not contain sewage. This includes dishwasher water, laundry water, bath water, food preparation water etc. This water is not immediately hazardous to health like sewage but no one would claim it is clean. Such water can contain"

• surfactants (soaps and detergents)
  
• high BOD material
  
• various chemical (e.g bleaches)
  
• alcohol
• suspended solids (coffee grounds etc.)
• plastic micro spheres
• dyes
• oils

and other pollutants.

If discharged to a water source it will contaminate that water.