The board may provide that rates, tolls, and charges for any sewage disposal enterprise or service may be collected with the rates, tolls, and charges for any water or other utility service rendered by the district, and that all rates may be billed upon the same bill and collected as one item. If charges for water and sewage disposal service are billed upon the same bill the district may discontinue water service in the event of failure to pay the whole or any part of the bill.