Update Trouble of the Worst Kind.Black Tank Won't Empty Help

Nothing comes out? Not even some liquid?

Are you sure when you pushed that hose 3' past the valve that was enough to get to the backside of the tank?

If you are brave enough to shove a running hose up the black drain you gotta go all the way until you see water movement from looking in the toilet.

I would be far more inclined to use a back flush fitting.

60C water sometimes works wonders

I had a similar issue the first time we used our Jayco in Pigeon Forge in Jan 2002. You never forget those things.

I bought some 3/8" thick wall polyethylene pipe and could push it into the tank but the hole would fill back in when the pipe was removed and the tank would not drain. Only a few ounces each time. What an unpleasant mess, went on for two days.

1st **) The way I overcame the issue was to buy a Flush King, using water to push the clog backward and break it up. Was mostly toilet tissue that did break up but seamed to pack together. From that day on we flushed twice if tissue was used.


2nd **) Found the cause about 9 years later. Removed the tank to fix a leak, there was an extra large #3 Craftsmen screw driver stuck in the elbow of the pipe along with the round piece of plastic cut out for the tank vent. The larger round piece of plastic cut out for the tank drain was still in the tank.


I haven't done the math but the pipe is about 3". At approximately 9 sq. in. and 50 psi water pressure that should be over 400 lbs pushing on the clog. In addition, the sewer hose can be attached to the Flush King while your doing this which makes it much less messy.


The Flush King is worth every penny when you need it. I've only needed it the one time, but carry it in the Jayco at all times.

Good luck

Is something FROZEN, as in ICE?

Oaklevel wrote:
Probably too much poo & paper and not enough water...... They make a power wand flusher that attaches to the garden hose to give pressure that might help.

I have one, I'm, going to try it tonight after work.

RJsfishin wrote:
This didn't just happen, Sounds like it has been building up,.....maybe since new, draining off nothing but the water, while the solid was building up, and getting dryer all the time to where it is now a solid block. You need to just slowly break it up w/ a full flow water hose, from the bottom first, and if no good, do it from the top. One thing about it, if you are the normal, you'll get it, one way or another, and you'll never let it happen again.
I had it happen once in 45 yrs.

I've rinsed it with the tank flusher religiously because of the feedback I've read on here. I always rinse until it runs clear.

j-d wrote:
Is something FROZEN, as in ICE?

No ice, the coldest it got at the lake was 33F.

Might pay to have the tank suctioned via the toilet opening. Then you get a better look at the problem. There might be a septic tank company that could help you out.

Sometimes the disc from cutting out the opening for the 3" pipe can be left in the tank and will plug the outlet. Who knows, since you've had the TT for a few years, maybe "someone" put something into the tank they shouldn't have.

After having an in-tank flusher, I have found that it works much better than a back-flush elbow, but you want to use it to clean your tank (when dumping at the CG) to get the tank clean before you head home. I only use our elbow now to watch what's coming out (and to provide an angled transition).

The solution is prevention. Add 4 or 5 gallons before you use the tank, use lots of water when flushing #2, and fill the tank up before you open the valve. Resist the temptation to skimp on water to extend the time before you need to dump the tank. If you delay cleaning it properly after each camping trip, you can make emptying and cleaning a real problem down the road. Again, you want to make sure it's thoroughly cleaned before you head home.

We have had trouble in the past with extreme difficulty in emptying our black tank. Some tanks are simply harder to dump and clean due to their dimensions and configuration. Some tanks, like ours, are shallower and long and harder to drain. After opening the valve, I run the tank flusher for 5+ minutes (while breaking camp) then fill the tank up (with foot valve) and dump. Then I look down the toilet and if the tank bottom is not spotless, I repeat the rinse, fill and dump process again. Takes me 2, or maybe 3 repetitions to get the tank spotless. The tank in our first TT was a piece of cake to dump and we never ever had an issue.

You might try getting a stiff, hard-walled garden hose and pushing it up into the tank and down into the tank to try and break up the solids and clear it. A plumbing snake might work in through the outlet.

If all else fails, you can use liquid drano. Our owner's manual actually says to use it if needed and we did use it once. It MUST be the version that does not attack metal and DO NOT ever dump it into an on-site septic disposal system or you can permanently damage it. If you use this, you'd want to tow your TT around a bit to slosh the contents around inside the tank. Your tank will end up clean as a whistle.

I am of the opinion that using the correct type of TP helps so that it breaks down when in the tank. Some RV brands of TP actually do not break down as you would think they should. Some ordinary household brands do break down, like one of the Costco brands we use. You can put a few sheets of your TP in a glass of water and see if it disintegrates into small pieces after a few hours.

Good luck and report back when you get it figured out.

ps: It helps to avoid long run-on paragraphs (like in 1st post) when posting and break your point/thoughts up into smaller paragraphs. Gets hard to wade through looong paragraphs. ;)

I know I'm stating the obvious, but there can only be two things either the valve is stuck closed, or you have a blockage.

Everything you did should have fixed the problem which means you either assuming/overlooking something, or not snaking it good enough.

Since you seem to be OK with snaking from the dumping area, I would buy about 10 feet of stiff PEX type tubing. Plumb a hose connection (with shut off) to one end of that tubing, connect the hose to it, open the valve, run the tubing up the line until you hit something, turn on the water and stand back. If you want a little safety, buy an end cap with a hose connection and run the tubing through that hose connection. That way when it give way you only have a 3/4 inch opening to deal with instead of a 4 inch one.

Good luck.