RV Plumbing Systems

• Recreational vehicles have a self-contained plumbing system. Almost every RV has a gray water tank that holds waste from the shower and the sink. There is an additional black water tank that holds waste from the toilet. These systems have sensors that show the RV owner when they are getting full and need to be flushed. Both systems are flushed by a single set of pipes. The owner switches a valve between the two tanks to indicate which tank will be flushed into the campground wastewater system.
  
  

Normal Black Water Flushing

• The best way to flush the waste system is to first flush the black water tank and then flush the gray water tank. This method makes sure that the cleanest water is passing through the system last and leaving the pipes as clean as possible. It's important to wait until the black water system is nearly full before it is flushed. The weight of the waste water in a full system will cause the solid waste to be forcefully flushed away. If the black water system was regularly flushed without being full there would not be enough to force to remove the solid waste and it would be left behind. This eventually would cause the black water system to clog.
  
  

Black Water Tank Clog Removal

• If a black water tank develops a clog, it has to be removed for the system to be able to be flushed properly. Recreational vehicle parts suppliers carry a wand that attaches to the end of a water hose. This wand has small openings in the end that spray high pressure water in several directions. To relieve the clog, extend the wand down the toilet opening directly into the black water tank and turn on the water. The high-pressure spray from the wand will dislodge the clog, allowing it to pass through the piping and go to the dump station sewer.