Keep those Waste Tanks Clean

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February 10, 2009

Keep those waste tanks clean:

We have found Original Dawn Dishwashing liquid to work for us as both full-timer and part-time Rvers.

This process may not work as well with those who do not move their rig very often.

Before we leave the campsite, we drain our tanks, close the drain valves and add ¼ cup of ORIGINAL Dawn dishwashing soap to 2 gallons of water.

After our arrival at the new campsite, we drain the sludge loosened from the inside of the tanks.    We add water to the closed tanks after draining.

It is best to keep the tanks closed during use and drain every 3-4 days.

If a smell develops, we add one half cup of baking soda and dilute it with more water and let it stand overnght.  PineSol will also help – but do not use too much (more than a cap full at a time) as it will cause your rubber seals to derogate.

I am lucky, my wife chooses to defecate in the campground comfort stations.  She also places her toilet tissue in the closed wastebasket in our restroom.  This wastebasket is emptied every 3-4 days. Why am I to argue with her way of doing things.

Rule #1 = If Momma’s not happy, no one is happy.


Happy Camping,

Fred b.



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  1. ddrsi

    eVER TRIED A SPLASH A LAVENDER pINE-sOL. Rad about here , like it.helps to clean up the Rv as well

  2. Albert

    J Christ is going to too much trouble . Billk has it right, Phill is draining his tanks properly! My motohome is 25 years old and over 100,000 miles and I could eat out of my black water tanks !! All these chemicals are for the birds except to keep the smell down when you are emptying them. I also can dump full tanks in about 3 minutes .I rinse My hose with grey water.

  3. Phil
    Rid-X only works on household septic tanks and takes a few days for the enzymes to begin to work, they work very well but only are helping the camp ground STP not your RV holding tanks. Dont waste your money on it..
    You havent had a problem because you are properly draining your tanks to begin with.

  4. Your black tank will stay quite clean with proper draining and rinsing. Installing a tornado tank rinser or similar device works very well, and requires only a few minutes of use at the dump station. I still use odor control chemicals if it’s going to be hot out but other than that, it’s frequent flushing that does the trick.

    Here’s a link on installing a tank rinser should you choose to install one (and you should!):

  5. Rich D.

    Why go to that trouble to “keep the tank clean”? It’s not like you are going to store something else in it next time.

  6. Phil Schoner

    I add about a cup of Rid-X to the toilet after every dump (the tank, not me). Been full timing 4 years and never had a problem.

    When I dump the black water tank I follow Monaco’s recommendation and allow the grey water to gravity flow back up into the black water tank. To do this I turn off the mercerating pump and open the drain valves on both holding tanks. Since these tanks are side-by-side, the nearly full grey water tank flows through the drain line manifold up into the black water tank until the two tanks are at the same level of water. The grey water has alot of detergent in it from normal washing, etc. and this soapy solution does a good job of cleaning the black water tank. I then pump out the black water tank and repeat the process.

    If you do not have a mercerating pump you can drain your black water tank by gravity, as normal. Then raise the end of the drain hose above the level of the holding tanks and open both drain valves. Grey water will then flow through the drain manifold up into the black water tank. Close the grey water drain valve and drain the grey water out of the black water tank.


  7. Roxie

    The tips on flushing out & keeping black tanks clean is great but Calgon Water Softner is not to be found anywhere, any more!!!!!!! If you have some secret supplier please let us know.
    Myself, I think that baking soda does the same thing. Softens and cleans and it’s biodegradeable and safe. Comments??

  8. Va. Patroit

    This is all a bunch of poop! 😉

  9. evie sanchez

    I like the way your wife thinks. My wife does the same thing. We’re big Dawn supporter for what they do to save wild life animals. I would rather clean with a chemical that gives back and what better company to use then DAWN.

  10. Casey Donovan

    der·o·gat·ed, der·o·gat·ing, der·o·gates
    v. intr.
    1. To take away; detract: an error that will derogate from your reputation.
    2. To deviate from a standard or expectation; go astray.
    v. tr.
    To disparage; belittle. See Synonyms at decry.

    Sure, I wouldn’t want my toilet seals to feel belittled, even in their unglamorous role — but I don’t think that’s what you had in mind.
    Maybe try “deteriorate”?

    With no apology for the poor humor, many RV’ers seem terribly anal about their toilets. Every time I read another posting of these multiple complex schemes for keeping them clean, I wonder, do you really expect to store food down there in some hypothetical emergency? I just dump mine when it needs it or when I leave a campground, pour a little blue stuff into it (it has to be blue), and rinse it with water once in a blue moon. I’ve never had any problems with odors or dumping, except when I’ve forgotten to remove the plug from the end of the dump hose.

  11. Jerry Thornton

    YUK, putting toilet paper in waste basket is so disgusting, new other people did that in their homes and will never go there again, what diseases and germs you can get is unbelievable…………

  12. PapPappy

    I don’t quite see why the DW will put her toilet paper in the trash…..the few sheets that are used by women when they urinate, won’t be clogging up any system. And, if you are using the toilet for #1 & #2….there is plenty of toilet paper added.

    I agree with previous posts about the use of the detergent (Dawn) and Calgon, and believe that the longer they are in the tank, the better. If you put it in the tank for a few hours, then dump it…you are wasting water and the soap. You might as well wait until the tank is full…then dump it!

  13. I learned last year from a rv shop owner about using a small box of Cheer or Tide, clothes washing granulated soap, to clean my black tank. I drain the tank before I leave then use one small box with 3 to 4 gallons of water. I do this when I’m moving from one campground to another. I flush it when I get to the next campground. It’s amazing how it cleans out the walls and top of the tank. You can pick up the small boxes at most campgrounds that have a laundrymat. The boxes run from $.50 to $ 1.00. Sorry no pictures to go with this….Fritz

  14. Even better, add a couple of bags of hard commercial ice cubes to the tank as well. Just pour them in the toilet. Do this just before hitting the road. The cubes serve to losen up debris so the dish soap can break it down. Just make sure you fill the tank 1/3 to 1/2 full with water. You may not want to do this however if you have inside the tank sprayers as the cubes could damage them.

  15. Fred,

    I know each to their own opinion, but frankly I think you are either being WAY too cautious or just going to a lot of unnecessary trouble.

    I’ve owned four motorhomes and helped countless other RV’ers with this and not one of them has had a lick of problems. I add 1/3 cup of Dawn Dishwashing Liquid each and every time I dump my tanks (no mixing with water) and it sits in there until the tank is dumped. What this does is help to keep the tank sensors clean.

    Then once every six months or so, I pour two cups of Calgon Water Softener into a gallon of hot water and add the mixture to the holding tank. Also add a cup of liquid laundry detergent to a gallon of hot water and add the mixture to the tank.

    Let it sit for several hours before topping off the tank with fresh water and letting the whole thing perk for a few more hours (preferably driving the coach).  That will allow the softener to release any deposits from the sides of the tank.

    When you drain the tank the softened & emulsified waste should come out in the discharge.  Rinse the tank and empty it a second time. This works for both Black & Grey water tanks.

    This has worked very nicely and never any odors and the system just keeps working flawlessly as it should. BTW, toilet tissue goes down the drain just like all bodily waste. And there is NO NEED to buy that expensive RV toilet tissue either. Been using Scott Brand single ply for years–I also use SEA-ZYME (a heaping teaspoon-in each tank) every time I dump the tanks. Again none of these expensive additives that you get at Camping World or other RV supply facilities.