How to Empty Your RV Holding Tanks

by Contributor

We all remember the scene in the movie RV where Robin Williams is trying to empty the RV's holdings tanks while the whole campground is watching. The ensuing comedy was a bit exaggerated but nevertheless embarrassing.

Don't let this be you. By following a few simple steps, emptying your holding tanks will be boringly uneventful. And you will be the letdown of the campground.

Start by pulling up to the dump station, placing your holding tank drain valve as close to the opening of the dump station as possible. This will ensure that if there is an accident, it will be contained in the dumping area.

Put the latex gloves on and get your sewer hose out. Before removing the cap to the holding tank drain opening, ensure both the gray and black water valves are both closed.

Check your sewer hose to ensure the hose is securely clamped to the adapter that attaches to the holding tank drain outlet. Remove the cap and attach the sewer hose, ensuring the adapter is completely attached. You can tell if it is when the tabs on the adapter are lined up with the stubs on the tank drain.

Insert the other end of the sewer hose into the dump station's hole about four to six inches. Use the hole's cover, a brick, or something heavy enough to hold the sewer hose in place so it doesn't come out of the hole.

If you have a permanent-mount black tank rinser, now is the time to connect it up to both the RV and the dump station water supply with the garden hose, then turn on the water.

Once you are certain everything is secured, pull open the BLACK water tank valve first. You will hear the effluent rush through the hose, start to slow down, and finally become a trickling sound.

If you have connected a black tank rinser, let this run for another minute or two to help remove solids left behind, then shut off the water and disconnect the garden hose. Now close the black water tank drain valve by pushing the handle completely closed.

Now open the gray tank valve. As in step 6, you'll hear water flow, then slow, and stop. Close the gray tank valve.

At this point, you're almost done. If you want to flush and rinse your tanks once more, you can do so by filling your tanks to 2/3 full (if you don't have a tank rinser) and repeat the emptying process. If others are waiting to use the dump station, be courteous and skip this step.

Recheck that both your black and gray water tank valves are closed and disconnect the sewer hose from your tank outlet. Replace the tank outlet cover.

Lift the end of the sewer hose (the end you just disconnected) to completely drain the hose into the dump station. If a non-potable water hose is available, run water through the sewer hose to rinse it out. Remove the sewer hose from the dump station hole and rinse the outside of the hose. Rinse the area around the hole to ensure that any spillage has been cleaned up and cover the dump station hole.

Go in to your RV and add about five gallons of water (about three full bowl flushes) to your black tank and then add the appropriate amount of holding tank treatment. If you use a treatment for your gray tank, do that as well. Do this only if no one is waiting in line to use the station because it can take a few minutes to do. If others are waiting, pull away from the dump station (don't forget your leveling board) and perform this step in another area.

The task of emptying your RV's holding tanks is now finished and you weren't the laughing stock of the campground!


  • check If possible, let your holding tanks get at least 2/3 full before dumping, especially the blank water tank. It needs the liquid to keep the solid waste in suspension.
  • check Always empty the black water tank first. Emptying the gray water second will rinse out the sewer hose.
  • check One way to tell if your black tank is completely empty and rinsed thoroughly is to use a clear sewer hose adapter at the connection point to the holding tank. You will be able to then see the effluent run clear and know when to stop rinsing.
  • check If possible, place the RV at a slight angle toward the dump station opening. You can do this by placing a leveling board under the right side wheel of the RV. This helps to drain the holding tanks more completely.
  • check If your holding tanks fill up before you're ready to leave and you don't want to break camp, often times there is a "honey wagon" service available that will empty your tanks at your site for a small fee. This is of course if your site does not have sewer hookups.


  • close If you make a mess, be courteous clean up after yourself. Don't leave it for the next person!

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About the Author

This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about It Still Runs, contact us.

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