Keep in mind that the holding tank in your RV is nothing like your septic tank at home. Your black tank is simply somewhere to hold waste but does not digest or eliminate anything. Plenty of water is necessary for maintaining a healthy holding tank. If everything is working properly and you just need the hose that runs from the holding tank to the sewer connection you will find these available at very RV dealer in the area or available on line if that's more convenient. There are many makes and models but they are all about the same.