Monday, September 25, 2023


How an automated RV dumping system works


Doug Swarts, the inventor of the Drain Master electric sewer valve, explains how the system permits an RVer to dump his or her holding tanks remotely from inside the RV. This is the same system that editor Chuck Woodbury installed in his motorhome. Read Chuck’s essay about his system here and/or watch the video below to see its developer explain how it works. The electronic valve demonstrated is the Drain Master S2VT Pro-Series Valve.

More information is available at or by contacting Doug at or (877) 787-8833.




Chuck Woodbury
Chuck Woodbury
I'm the founder and publisher of I've been a writer and publisher for most of my adult life, and spent a total of at least a half-dozen years of that time traveling the USA and Canada in a motorhome.


  1. It’s not fully automated. The Smart Tank System from is fully automated. It will connect to the Drain master or Valtera. I haven’t manually dumped my black or Grey tank in 2 years. The sensors will open any electric valve, rinse and close it after 5 or 10 minutes while the solenoid valve will open and flush for the times pan. It’s an amazing RV invention!!

    • Kiwi, the hose always stays connected and when not being used there is a shut off at the end. So if the button should be accidentally pushed, the worst that would happen is the tank would dump until it reached the end of the hose, where it would be blocked. In that case you would need to get to a dump station, insert the hose and pull the open lever. Mistake dealt with easily.

    • RVgrandma
      We do not have a specific heater for our valves; however, a number of customers in cold weather conditions tell how well they work with heat tape. Here is one customer’s comment:
      “Wanted to let you know, I lived in an RV 4 years in the oil field in North Dakota. 1st year, dug snow out from around my dump valve, that was double wrapped in heat tape to dump my holding tank. and was still froze shut at times. Installed your Drain master dump valve, and wrapped it once with heat tape, worked for 2 years, never failed. Even in -36 degree temps and -62 wind chill.”
      If you would like to talk about this please give me a call 877 787 8833 Toll free or email me doug (at)

  2. I guess I’m too thick to get it. The “automated” part of the automated dumping system is the powered valve? One still has to go outside to hook up the hoses to the black and grey water tanks, right? And one still has to unhook the hoses from the tanks and flush them and put them away, right…? So the one part of the job that is usually the cleanest (pulling the handle to open the valve) and easiest is the powered part of the process? Whatever happened to the K.I.S.S. principle?

    • Hi John,
      Actually Both Chuck and Greg’s sewer hose is permanently connected to their RVs using industrial grade Cam Loc fittings so all they do is pull the nozzle out of their water bays and insert it in the ground sewer inlet. When they feel it is in there securely, they open the valve in the nozzle then go to their RV and push the button to Open the Black valve. The standard dumping practiced by everyone is used, i.e., Black first followed by the Gray — we did NOT change any of that part of the process. If sitting in a park for a period of time, as Chuck and Gail are currently, Chuck has left the nozzle in the ground sewer inlet so he has the convenience of simply looking out at the nozzle to insure someone didn’t knock it out, then he pushes the buttons inside the bathroom to dump. Chuck or Gail will probably have dumped their Gray tank 10 to 20 times before they leave the current park (I think they have been arguing over who gets to dump). When they are ready to leave for drier land, Chuck or Gail will dump and flush their tanks, then go out to the sewer inlet, CLOSE the nozzle valve and collapse the hose back into the compartment. They will neither clean out the hose NOR disconnect it from the RV. And that, John, is what I consider K.I.S.S. at its finest! All of the components in this system are designed to industrial standards to insure a secure, uneventful, sanitary and environmentally friendly dumping experience. If you have any question please feel free to contact me.

      Editor: You can contact Doug by email at doug (at) or call him at 877-787-8833.

  3. I enjoyed your short video very much. I have been fifth wheeling for a number of years and knew about not leaving dump valves open all of the time so pulling the handle now and then is no problem. Quality control of newer RVs is however. A fellow told me a long time ago that they are all junk and I have a tendency to believe him. In 1972 I built a slide in camper and it was the best of all. I purchase a new fifth wheel in December 2015 and had and still have it’s issues. When I got it the stickers for the grey and black dump handles were reversed. So you can appreciate how it was when I went to dump the grey water in a grey water disposal area. Closet doors do not stay closed when travelling, in fact many times they fall in the closet. Drawers not staying closed when travelling. Slide not sliding properly and other annoying things. However the dealer said everything was checked and was fine. The manufacturers have to pay more attention to detail and the dealers have to pay more attention to their predelivery checks. For example it took many phone calls, emails, and visits to the dealer to try to find out how to turn the light on over the fifth wheel king pin. No one knew, the customer service at Keystone or the dealer. And the owners manual is a generic one that is useless so I finally found it by accident when I turned on the scare lights with the remote and I was outside. If I were younger I would buy a truck and chassis and build one myself. I built an office unit from a construction trailer some seventeen years ago and it still being used by a company and he loves it. Thanks for giving me the opportunity to ramble on also.

  4. Re: The ‘remote controlled’ RV tank dump valves.

    I would prefer to see what comes out of the tanks, especially black, so that I can see if any TP wads are still coming when I flush
    I forsee that one can close a valve not knowing that there is a wad of TP trapped in the slide.

    • Mel,
      We have a clear view fitting right behind the sewer nozzle to insure the tanks as well as the hose is clean. By keeping your Gray tank closed until it is 3/4th full your chances of TP issues are reduced dramatically! Also having a 3″ valve on your Gray tank really helps keep the Gray tank cleaner AND does a much better job of cleaning the sewer hose.


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