We need gravity.  It keeps our wheels on the road, and from an RV perspective, it’s what makes our waste plumbing work.  In an RV, all drains lead to Holding Tanks.  Holding tanks are the built-in tanks that hold any liquid waste coming from your RV.  Tanks that hold wastewater coming from sinks and showers are called “gray” tanks.  Tanks that hold toilet sewage are “black” tanks.  Typically, there is one black tank and one or more gray tanks.  The easiest way to know if the tank is gray or black is to look at the waste valves that drain each tank.  The waste valves are located near the holding tank exit where the sewer hose is attached.  The gray valve is the smaller valve (typically 1.5 inches).  The black valve is the large valve (typically three inches).
It’s important to have the RV as level as possible when draining the tanks.  Since gray tanks hold all wastewater, you need to be careful what you put down the drain.  Food or other large items may not flush out when the tanks are dumped.  That can cause odor or interfere with the waste valve operation.
It’s important to always have plenty of water in the tank before dumping.  For this reason, I would recommend not leaving the gray waste valve open while camping.  Let the water level build; it’ll help flush out all items when dumping.  This is also important with black tank.  Solids will be at the bottom of the tank.  Water buildup will help remove the solids during dumping.  For those of you who live in your RVs and are connected to sewer systems, I would recommend that you follow this procedure with the black tank.  The correct sequence is to dump the sewage first.  Open only the black tank waste valve.  Allow a few minutes for the tank to empty.  Go inside the RV and flush the toilet.  Allow water to run down the toilet to help flush the tank.  Close the black tank valve.  Next, drain the gray water tanks.  The gray wastewater exiting will help wash out the black tank waste in the drain hose.  Finally, make sure all waste valves are closed before removing the discharge hose.
Be safe and enjoy the RV life.
Final Touch Coach Works is located at 28532 Livingston Avenue in Valencia.  For more information, please call 661-775-8375 and visit www.FinalTouchRV.com.