Black tank odor

[Derby6]

So my black tank is stinking inside and it’s getting really bad.

I think it’s a thetford toilet. Original to unit 2007. I’ve owned since new and this had never been an issue.

Pored some water in both roof vents and could hear it land in tank. So they not clogged right?
Toilet is holding water so it’s not coming thru there.
I can smell it really strong when my nose is near the top rear of toilet (right side as you face it). Water valve is on top left.
Obviously the worst smell when I flush-which I could deal with but it’s constant odor at this point.
No water leaks at all. And toilet is secured.
Is there a valve of some sort that could be letting this order through? Or do I just need a new toilet.

I’m using it for work this month. Mainly sleep —not in it much but I have used the toilet. Time permitting My plan today is to go and dump it and flush it with a whole bunch of water and fill it about 1/2 with water . (I’m dry camped)

This is first use this year.
Figured I’d see if anybody had any ideas.

 

[Ohiosnowbird]

We’ve had a similar issue. It was because we were parked for a long time and a large amount of TP settled and didn’t discharge on dumping. Once it collects, that smell is everywhere until you get it cleaned out. Just my 2 cents.

 

[Derby6]

Thanks I’m headed to dump and give it a heck of a rinse now we’ll see what happens

 

[climberbob]

So my black tank is stinking inside and it’s getting really bad.

I think it’s a thetford toilet. Original to unit 2007. I’ve owned since new and this had never been an issue.

Pored some water in both roof vents and could hear it land in tank. So they not clogged right?
Toilet is holding water so it’s not coming thru there.
I can smell it really strong when my nose is near the top rear of toilet (right side as you face it). Water valve is on top left.
Obviously the worst smell when I flush-which I could deal with but it’s constant odor at this point.
No water leaks at all. And toilet is secured.
Is there a valve of some sort that could be letting this order through? Or do I just need a new toilet.

I’m using it for work this month. Mainly sleep —not in it much but I have used the toilet. Time permitting My plan today is to go and dump it and flush it with a whole bunch of water and fill it about 1/2 with water . (I’m dry camped)

This is first use this year.
Figured I’d see if anybody had any ideas.

My toilet started to stink because it had old stuff in it that wasn't completely cleaned out from before. I flushed it about seven times and after that the smell went away. Good luck!

 

[rvlifer]

there should be a vent for the smell to escape. Make sure that isnt blocked. Are you using any chemicals in the toilet?

Black tanks take some getting used to so they work properly. You cant let them get too low with water or too full. If you dont add some water after you dump them, or rinse them enough, you could have problems with them.

If you have the money and interest composting toilets can be far easier and pleasant to deal with

 

[Mark_K5LXP]

Does the bathroom sink drain into the black tank? There could be an admittance valve that's un-admitting.

Mark B.
Albuquerque, NM

 

[DutchmenSport]

When you flush, is your ceiling vent fan running. If so, turn it off first before flushing. That fan will suck air (backwards), from the roof vent, into the black tank, and then the air "draw" will suck up the black tank odors up through the open valve in the toilet when you flush.

So, turn that fan off.

As far as keeping your black tank cleaned out, you should start back-flushing the grey tank into the black tank, EVERY time you dump your black tank. It's easy to do and it keeps the black tank cleaned out. And takes no extra water to do it.

 

[Wilbur3]

Get the Flush King adapter between dump connection and hose. Fill tank with water; drain about three times or more until drained water runs clean. Following last flush, add a few gallons water to tank with chemicals. If the tank vent pipe thru roof is near bathroom ceiling vent, the wind might push odor inside.

 

[Derby6]

My toilet started to stink because it had old stuff in it that wasn't completely cleaned out from before. I flushed it about seven times and after that the smell went away. Good luck!

I think that is my issue. I don’t use a lot of chemicals and I never had a clear tube to see this one when I dump so I think I may not have got a good clean last year. But it’s been getting worse. It’s been a little over two weeks.

there should be a vent for the smell to escape. Make sure that isnt blocked. Are you using any chemicals in the toilet?

Black tanks take some getting used to so they work properly. You cant let them get too low with water or too full. If you dont add some water after you dump them, or rinse them enough, you could have problems with them.

If you have the money and interest composting toilets can be far easier and pleasant to deal with

Checked the vent, but I’m on my way to do a second dump. I filled it with clean water. I’m gonna jam my battery powered pressure washer down the vents just to make sure they are clear.

Does the bathroom sink drain into the black tank? There could be an admittance valve that's un-admitting.

Mark B.
Albuquerque, NM

My sinks and shower goes into the gray the tub on this unit shower and toilet in one room sinks in different one.

When you flush, is your ceiling vent fan running. If so, turn it off first before flushing. That fan will suck air (backwards), from the roof vent, into the black tank, and then the air "draw" will suck up the black tank odors up through the open valve in the toilet when you flush.

So, turn that fan off.

As far as keeping your black tank cleaned out, you should start back-flushing the grey tank into the black tank, EVERY time you dump your black tank. It's easy to do and it keeps the black tank cleaned out. And takes no extra water to do it.

Yes sir fan off tracking that been there done that. Lol
I just learned that backflush technique and I do that in my fiver, but I don’t have the extra valve here for this one.

Thank you all!!!!

So I dumped and then filled it completely full with chemicals drove around. Let it soak for a while. On my way to drain it again and see what gives. I always use lots of water, but I’m a little worried. Maybe I have some buildup in there because I’ve never used that clear piece to know when I dump if it’s really clean. But I just bought one for this.

My other concern is no matter how rancid the smell was. I shouldn’t be getting it in the camper if it was only in the black tank. Somehow the toilet is or was allowing the smell to come back in.

 

[Mark_K5LXP]

no matter how rancid the smell was. I shouldn’t be getting it in the camper

Right. Rinsing, treating, washing and potions shouldn't make a difference - it's a holding tank vented outside. I don't care what you do to the tank, it will never be april fresh so your problem isn't what's in there, it's how it's getting to the interior. Could be a vent pipe gone awry, a seal somewhere or even a busted tank. Just need to eliminate the possibilities until you find it.

Mark B.
Albuquerque, NM

 

[rvlifer]

Try the bag of ice trick the next time you move the rv. Dump tge ice down the toilet into the black tank before you leave. It is supposed to help break up stuff stuck in the tank. May not help but it wont hurt

 

[bigbAZ]

If you have a Thetford Aqua Magic the only thing that keeps odors from coming up around the flush arm is a flimsy foam gasket and some grease which could be gone by now.

 

[Derby6]

Did the ice when I left..
After filling with chem, lil drive and soak it came out Crystal clear. cleaned as I inspected--toilet never been so clean in and out. Aired out and was feeling good.
Battery powered pressure washer down both vent pipes (not sure which was gray and black so they both got it). Flashlight proved tank is clean I really do use lots of water and sani flush the heck every use.

More cleaner and a 2-5 gallons of water and now Im back and reset camp. As I type this I think I am getting the smell.

 

[Derby6]

If you have a Thetford Aqua Magic the only thing that keeps odors from coming up around the flush arm is a flimsy foam gasket and some grease which could be gone by now.

View attachment 1321970

I think you nailed it. That is my toilet--Just pulled out my book. Its a Aqua Majic V and that pic shows EXACTLY where the smell is VERY strong. Now i gotta figure out how to repair it or if I have to replace.

 

[zulutron]

Have you tried a couple cups of bleach?

 

[Derby6]

No Bleach---
I am over 95% sure bigb56 nailed it. I tried to completely enclose the entire rear of the toilet with painters tape and paper towels hoping the will contain smell until I can take out toilet and repair or replace. That could take some time. I hope this works!!

 

[Kirk]

I hope this works!!

I have found that the odor from the gray water tank can be as bad or worse than that from the black. If the air admittance valve fails it will allow odors from the gray tank into the RV. The problem becomes far worse if you leave the gray water dump valve open, but it still happens with the dump valve closed. The valves are inexpensive and very easy to replace. Look up under the sink to see yours.

Most RVs come with the type shown in the picture, as they cost the least but they also fail most often and last the least time. I have found that the ones from Oatley or from Dual Seal to be much more effective and to last far longer. Another good one comes from Studor.

 

[Rene T]

Look up under the sink to see yours.
View attachment 1322009
Most RVs come with the type shown in the picture, as they cost the least but they also fail most often and last the least time.

As a quick check, just slide a baggy over the valve and tape it real good. Then see if the smell goes away

 

[Derby6]

I concur gray water can also be pretty rancid. But this is my toilet/black tank.
Painted tape and paper towels did the trick and I can still use it. Just gotta figure out when I can get to town to get a new toilet.

 

[bigbAZ]

I ordered mine from Amazon about 4 years ago. Unfortunately due to wall clearance the Aqua Magic V is the only toilet made that will fit our small bath so we had to stick with the same model. If you have more clearance you have the option of choosing a better toilet. I was hoping you'd try and fix it though just so I';d know if it were possible! We ordered a new one because ours had several issues plus we did not want to deal with cleaning up someone else's old toilet.