Forum Discussion

tlnibert's avatar
tlnibert
Explorer
May 09, 2014

Black water tank

A friend set his rv at a campground for the summer. He left the tank gate valve open and after several weeks he has a stopped up tank he can no longer use. He says the toilet is hooked to the tank by a pipe. I thought all rv's the wasted dropped straight into the tank.
Any suggestions??
  • Buy a bottle of Calgon water softener. dump it in with hot water until the tank is full of the hot water. Let sit one day. If you can get to the black tank straight down from the toilet, insert PVC pipe and stir what you can, dump what comes out, repeat until you think you have most gone. Then for the next few weeks, keep putting in the calgon water softener and blue treatments to try and remove all residue. This is a hard lesson learned. Be sure you use the Calgon in the laundry aisle - white bottle. It softens and makes all things slippery. Good luck.
  • They don’t all drop straight down into the tank… he needs to flush, and flush and flush…
    Back flushing would be a good start…
  • donn0128 wrote:
    AWWW the dreaded poo pile. Good luck. Close the tank, fill it with water and let it sit for a week or so. Open valve, drain and pray a lot. Then try all of the ideas above.


    x2. It may be worth adding water softener to the water?
  • This is a fairly common mistake done by inexperienced rv'ers....especially those absolute first timers. Rv black tanks require water to move the solids from the tank to the sewer....no water, no movement (no pun intended). Leaving the black tank discharge valve open allows the small amount of liquids to run to the sewer without moving the solids. Therefore, the solid build up in a pile until it blocks the tank.

    The requirement is to keep the black tank valve closed until 2/3rds to 3/4ers full, then open the valve to empty. Adding additional water to the tank to make it full, will help.


    Ron
  • AWWW the dreaded poo pile. Good luck. Close the tank, fill it with water and let it sit for a week or so. Open valve, drain and pray a lot. Then try all of the ideas above.
  • Not good for your friend. He will have some unpleasant work to do to clear the dried pyramid.
    Beside what has already been correctly suggested above, maybe something like this would work.

    Seriously, leaving the black tank valve open is most always going to result in this kind of problem..

  • He could try one of the attachments that go on the sewer pipe that allows you to hook up a garden hose and backflush from there.

    Or try one of the rotating wands that you stick in through the toilet.

    Or try dumping lots of hot water into the tank through the toilet, then ram some 1/2 inch pcv down the hole to break it up.
  • As far as I know, all drop right into the tank. He probably has a huge pile of dried poop clogging everything up. He may want to try one of those wands with the spray heads on it. Never leave the black dump valve opened!