Greywater systems function in sequestering used indoor water, such as laundry, bath and sink water, and filtering it for reuse. Greywater can be reused in irrigation and toilet flushing. There are two types of greywater systems: gravity fed manual systems and package systems.[72] The manual systems do not require electricity but may require a larger yard space.[72] The package systems require electricity but are self-contained and can be installed indoors.[72]