Clearing a Clogged RV Black Tank: Another Viewpoint

Clearing a Clogged RV Black Tank: Another Viewpoint

As I said in my previous post this topic usually generates lost of comments.  The comment below come form friend and fellow RVer.  Since his comments are extensive I thought they warranted there own post.:

While I never use chemicals, I’ve never said it would not work.  I just think there are better ways.  On the down side, cleaning with chemicals is very slow and expensive.  It will take several to many applications.

I am a more pro-active person.  When I have a problem, I solve it.  While I have never had this problem due to my actions, I once bought an RV that did and I have helped several people who had this problem.  I solve the problem this way:

  1. My first consideration is, how much time do I have?  If the RV is parked for several weeks you can attack the problem in stages.  If they are living in it, can they use the camp facilities?
  2. Next in importance, is the RV hooked up to a sewer system?  It is impossible to clean the RV’s black tank if it is not hooked up to a sewer.
  3. Will water drain freely from the tank, or has the pyramid covered the drain?  As long as I can get a trickle of water I know I can attack the problem with water.  If the drain is plugged, you have to be very careful not to over fill the black tank.
  4. If I have drainage and I have several weeks, I will put in a cup of Rid-X, fill the tank with water and let it sit for a week.  This will soften the mound and make it easier to chip away at.  I am not attempting to completely clear the tank here, but to make the mound more amenable to reduction.
  5. If I do not have drainage that becomes priority one.  In this case I go directly to work with a long toilet spray wand.  I must attain some drainage.  I jab the wand down into the mound as far as I can and then turn it on.  I use low pressure to prevent filling the tank.  Once I have a little drainage, I will work in stages, never letting the tank fill.
  6. If time is of the essence, I go right to work with the wand.  It never takes longer than a few hours, but it is hard work.  You are in and out of the RV, filling and draining the tank, opening and closing the valve.
  7. My favorite method is to put the spray wand into the top of the mound and then press down at an angle, then I turn the water on.  The easiest path for for the water is back up the hole created by the wand.  If you go straight down, the ugly water may spray back in your face.  I have plugged the hole in the bottom of the toilet with a rag to prevent spray-back.  I try to destroy the mound from the inside out.  The object is to saturate the mound with water to help soften it.  Just keep the wand moving.
  8. From here on it is just wand on, wand off, valve closed, valve open.  If I have time, I like to fill the tank and let it sit for several hours or overnight.
  9. When I think I am done, I fill the tank half way, put in ten pounds of crushed ice and go for a drive.  Then I fill and drain several more times.

As you suggested, I leave the black tank valve closed until it is around 3/4 full.  And, I always use Rid-X.  It generally takes me two weeks to fill that tank.  I use a variety of my black tank, camp facilities and facilities I come across during the day.  The Rid-X, for want of a better word, emulsifies the contents of the tank.  It is a simple bacteria that breaks down lumps and clumps.  If I were cleaning the tank more often than once a week, I would not bother with the Rid-X.  It works best when it has time.

Going forward I will not own an RV that does not have a built in tank spray system.  It really helps.  However, if you generally leave your black tank valve open, you will have a problem.

I hope this helps.

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25 Responses to "Clearing a Clogged RV Black Tank: Another Viewpoint"

  1. I recently had a blocage and was told to try 5 gallons of bleach dumped down the toilet and to wait 24 hours. the next day after pulling the valve the result a flush of clear water came forth and the clog was gone…

  2. While bleach will “oxidize” fecal matter, it will also kill the bacteria in a septic system. So, if the resultant material is to be dumped in a campground’s septic tank, the campground owner should discourage its use, especially five gallons at a time. Five gallons of bleach in a municipal sewage treatment system, however, is unlikely to cause an upset both because the treatment process is different and because the volume of materials is so large.

    When I used to own a campground, we cleaned a number of clogs with the pressure washer (and a full face shield – shower immediately after). Owning a campground wasn’t all glory.

  3. Linda Kalinowski · Edit

    A similar question is how do you clean the probes from a gray or black water tank to get an accurate reading of the tank level. We have tried products labelled to do just that with no success and are now in the process of filling tank and flushing extensively with a back flush of water.

  4. Even if you can get them reading properly, there just isn’t any way to keep the stock probes working for very long. There are aftermarket probes available that claim to work and looking at the design they may live up to the claim. They are called Horst Miracle Probes. If you try them please let me know how they worked for you.

  5. We have solved this issue altogether and for good without using harsh chemicals or wasting your time. See our web-site and learn for yourself why you don’t have to be concerned about black/gray tank issues any longer.

  6. I had two friends that had this problem in their fifth wheels. We were sitting in a park for six months. Both had clogged up toilets.
    I believe the problem was do to two things:
    1. Using 2 ply toilet paper, and the wife using lots of it.
    2. Not putting enough water in the tank after emptying it.
    3. Leaving the blackwater valve open.
    The fix. Use single ply paper. Scotts, 1000 sheet works just fine.
    Put at least five gallons in the tank after emptying it and keep the valve closed until it is full and ready to dump.
    Anybody who does not use a chemical that masks the odor when it is hot out most not have any friends.

  7. Does the RV toilet (I have a Thetford Aqua Magic 5 I think) drain pipe just go down and angle 90 degrees and drop into the black tank, or is there a vertical elbow or trap or something before it drops into tank? I am having drainage issues and I am using a flexible hose wand, but I can’t tell if the hose is going down and angling and right into the tank or thru another trap. I am concerned about damaging a seal if there is one down there, by ramming that wand down into it.

  8. Usually the toilet just dumps straight down into the black tank. The exception is on fifth wheels where the toilet is in the upper level. In this case there could be an angle in the drain for the toilet to the tank. If that’s the case it should be evident inside a storage compartment. You cannot damage anything with a toilet wand.

  9. We have a fifth wheel and the sewer was blocked a few weeks ago. We used a 3 ft snake and released the blockage. Now, for several weeks we’ve been going through the same thing. After we use the toilet a couple of times, the sewer blocks up to the toilet opening. We use the snake when it fills and when the snake reaches the 3ft mark down the hole, everything releases and all the material rushes down the pipe. Is this just a problem that can be fixed with hot water or do we need to replace pipes? Is there a trap that isn’t working correctly that we keep opeining with the snake? We have a new toilet purchased but don’t want to install it until we find out what the problem is. Please help. Thank you.

  10. Our fifth wheel plugged at the drain valve itself,sitting at a RV site for months. not wanting to move the trailer to a commercial dump station or risk a mess, I just ran a clothes hanger right thru the neck of the drain hose outside, taped over the hole and hanger where it entered the hose and used it as a small snake to go thru the plug from the outside in, taping over the hole and hanger worked as a seal preventing any mess and could still run the hanger in and out of the line. after emptying it I just trimmed the drain hose up an inch to get rid of the hole.

  11. We live in a 5th wheel trailer at an RV site. Our toilet clogs constantly. Even with the special TP. From what I’m reading, the problem is that we leave the valve open at all times. We thought the problem was the design of the trailer (It’s a grand junction). From what I’m reading I think we’re doing something wrong. Any tips you can provide for folks who live in their trailer long term? It’s a real problem. We use Magic Bullet to unclog but it’s once a week and I know there must be a better way to go about this. Thanks for any help!

  12. You’re right… the Black tank drain valve needs to remain closed until full. Also, once the tank is emptied and the valve closed again, you should add 2-3 gallons of water to the tank then use extra water when flushing solids.

    Learn more from these articles:

    RV Gray Water & Black Water Holding Tank Basics

    RV Waste Water System Care & Maintenance

  13. I just bought a 94 Jayco RK3050 5th wheel for full time living (first time owning a trailer), and noticed that the black water tank is not letting anything out. We used Ridx a week ago, and nothing is draining yet. The tank is 3/4 full and with the valve open, nothing happens. We are hooked into a septic tank and our grey water tanks drain fine, so the clog has to be either in the tank or at the valve. When I open/close the black water valve, it feels different than the 2 grey water valves. Seems “looser”, and other times, “harder” to open/close. My thoughts are that it might have broken off, and the valve isn’t opening at all. Any thoughts?

    Thanks, Scott

  14. Scott we have a 2011 Jayco Super light eagle and last year had a major clog. Turned out the handle came un screwed! Try screwing it back in. My problem is does righty tightly. Lefty lousy apply to these handles? I’m not sure. I worry all the time my husband might be un loosen it again. Our biggest problem is were not sure all the toilet paper is being flushed out and building up. We only use it for emergency bowel movements. Once you have it back up into the camper were afraid it will happen again. What a mess! We are still fairly New to a Fifth Wheel. Had a Pop-up before no toilet. He empties about every other Day. It has an outside hookup for a hose to flush it which helps! Do you think if we poured Hot water down it would help loosen any build up, Steve?

  15. If you are having problems with your Rv Toilet Cloged . The simplest and
    Fastest fix is to buy the Amazing New Twister . It’s a Rv Toilet Plunger it’s
    For sale on EBay. With a few simple Twist the
    Waste Pile is gone. Pile Moving Magic the Twister.

  16. I’ve been having some blockage issues with my black water tank draining. I’ve tried all the above except for the bleach because I heard it could damage your rv sewage system. a couple years ago I had a friend put Drano down my toilet which caused it to explode. So lesson learned and after replacing the black tank itself I find I still have issues regarding blockage. What is the best solution to digest tissue and solid inside

    black tank that won’t cost me a lot of money. Or is there somebody that can be recommended as far as a local mobile RV service handyman near everett WA that I can come to me if need be? I’ve looked online everywhere with only one person 100 miles away from where I am permanently parked.

  17. Having trouble with a blocked shower. We have tried everything but nothing seems to work Tried vinegar and baking soda. Tried hot water. Tried plunger Has any one got any ideas. We have a 1993 Kustom Koach fifth wheel

  18. Go to your local home store and get a drain snake. Get the one that looks like a mini plumber’s snake not the flat ‘tape’ kind. Get one at long enough to snake the whole line down to the holding tank. If you are lucky you should be able to get by with 25 feet. I’m stuck for a solution if that doesn’t clear clear the drain.

  19. First time Rver, rented a class A for a week some years ago. Not knowing any better, left the drains wide open all week. Just before leaving, toilet is plugged up. Not having any tools or supplies, solved the problem with gravity. Closed the drain valve and tied a rope to the sewer flex line, looping it snugly every foot or so. Ran the rope and the flex line straight up the side of the class A until the end was at the roof, about 12 feet high. Put my 12 year old son on the roof with the hose and slowly filled the flex line with water. 12 feet of water creates a reasonable amount of water pressure. quickly opening the drain valve forced the blockage out of the way. Stationed the wife by the toilet to watch for movement and quickly closed the drain valve before I created a massive overflow. Worked great and had an interesting story to share with the owner when I returned the RV.

  20. I’ve heard a lot of creative ways to unclog a black tank, but that’s a new one Tim. I am glad it worked for you but I have to admit I had visions of the Robin Williams movie RV while I was reading your comment. 8-)

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