Poop Pyramid

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Hi Everyone,

First time Posting! My name is Jon and I recently purchased an older 1994 Nomad Fifth Wheel. This unit was stored inside and rarely taken out so it is in great shape.Anyways, I seem to have an issue with the Black Tank. When I empty the tank a horrible odor appears in the trailer, mostly in the basement, but moves into the trailer. It only occurs when I empty the tank, while flushing or sitting, there is no smell. I wait to empty the tank until it is full. I flush it properly per all of the YouTube videos I have seen online. I close both Gray water valves, I climbed on the roof and I can smell the black tank through the vent so it isn’t clogged. I read online that there could be a leak, so they recommended filling the black tank up into the bowl and look under the trailer for any leaks. (The black tank is mounted under the trailer). There was a few drops running off the top of the tank, which could mean there is a small leak, but I cannot see it so I was thinking it could be the seal between the toilet and/or the vent. Has anyone else had a similar issue? If so, what did you so to fix it.

Thank You


« Reply #1 on: Today at 02:51:58 PM »


You are suffering from the dreaded poop pyramid. This occurs when people use the black tank wrong. What they do is park it someplace hooked up to the sewer and leave the black tank valve open all the time. This means there is not enough liquid to empty the tank and send the poop to the actual sewer. So poop builds up in the spot where the toilet empties into  the tank. What you should do is always keep the black tank valve closed when you are parked and when the tank is at least three quarters full then you empty it. And whenever you use the toilet use a lot of water. The chemicals are worthless.

Now what you can do to get rid of the problem is to buy a flexible black tank wand like this:


Turn off the water to the RV, open the flush valve on the toilet and block it open. Then hook up the wand and run it into the bathroom through the window, put the wand down the toilet and spend at least a half an hour hosing down the inside of your tank. It helps to have a clear pipe hooked up between the black tank outlet and the sewer hose like this:


Then have someone outside watching the clear pipe while you are inside spraying. When the water runs clear for about five minutes your problem will be solved. Like I said it will take at least a half an hour of spraying before the water runs clear because typically the poop pyramid is as hard as cement from sitting in a very hot black tank. And in the future you will always remember to use a whole lot of water. After I dump I put about five gallons of water in the black tank to start off with. Every time I flush I count to five before I release the handle. Poop pyramids will breed flies in a lot of cases so if you are seeing flies in the RV that is the source.

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