Grey water is used water produced during such activities as, e.g. bathing, cleaning, washing or dishwashing. Its name originates from the specific color that water takes on when contaminated by detergents and pollution. To recover grey water, we must first have the capability of separating it from the stream of sewage and from biological contaminants originating from bathrooms. For this purpose, it is worth leading a separate wastewater installation intended for draining off grey water to the appropriate storage tanks at the stage of designing an office or residential building.