Why does my toilet stink sometimes? Black tank..

[TMG51]

I have a class B with gray and black tanks. Thing is, I never use the toilet... I don't want to have to deal with emptying a black tank so I never put poo in it. Once or twice I've let a lady friend pee in it when other methods were harder to sell socially. But that's it. Several times I've run clean water in there and emptied it just to try to rinse any old stuff out if it's in there. The water comes out looking clear.

Lately though I've started to notice a strong smell sometimes. It comes and goes.

The water supply to the toilet had a leak so I capped it off. So, the toilet bowl does not have water in it. I thought maybe the seal was drying out so I've experimented with filling the bowl with water. I still notice the smell (intermittently). I run fresh water through the tank and empty it and it seems better for a few days and then the smell comes back.

I've also checked that the vent to the tank is clear.

So why does my toilet sometimes stink? Should I take it apart and replace seals? Dump some holding tank treatment down there? I've never done anything special with it because, like I said, the toilet is a non-issue for me. I've even considered just removing the toilet and covering the hole because I don't use it and I don't want my van to have a smell in it.

 

[rvpopeye]

Put some water in a balloon big enough to cover the valve in the john. sealed.
Things to try for getting rid of any residual smells......... the bacteria is in there.
Holding tank treatment/perfume , vinegar , rid-x,,,, bleach is a bit harsh on the seals but if you rinse well....?

 

[Gary68]

if you dont have water in the bowl air will push down your vent line and up your toilet,there could be some left overs stuck in the tank,sure it isnt your catalytic converter,tire rubbing,dead mouse in the heater or your upper lip?

maybe try the half full tank with ice in it thing and see if anything comes out,then some bacteria killing whatever

 

[TMG51]

Bacteria, yeah... that's probably what it is...

One time I had a bottle of dish detergent break and so I dumped the liquid down the toilet just to get rid of it. THAT was a mistake. The next time I opened the toilet valve, days later, liquid rose up into the bowl from all the froth of the soap sloshing around! I emptied it and rinsed it out until the soap went away. So I was thinking it was pretty clean after that.

It must be that bacteria has ended up breeding in there after. I guess I'll try dumping stuff in there with that in mind.

 

[Theadyn]

Fill it up with water and a treatment and slosh it around driving some to kill off the bacteria, maybe?

I've always put some kind of treatment down my black tanks, for just this very reason. No one wants stinky toilet, lol.

 

[Stargazer]

You don't detail the rinse process so if you've tried this, I apologize. But it is possible that solid wastes dried and a simple rinse won't do it. Try filling the tank with a water hose through the toilet valve instead of just flushing to get water in the tank. You want some pressure to break loose anything stuck on the bottom of the tank. When full, let it sit and soak for 24 hours (use RV tank chemicals if you can) then dump and rinse, again using the hose through the toilet for the higher water pressure it affords. This has worked for me and others who have had the same problem. A friend and neighbor had this problem with his RV, which he purchased used and had been sitting for several years. It took several times to finally get it clean and odor free.

Also, are you sure it's the black tank? Gray water tanks can actually smell worse than black. I will occasionally fill the gray with water (can't use a hose due to the U-trap), add a double dose of tank chemicals and let it soak for at least a day, then dump and fill and dump again. Every couple of months. Also, preventive measures include wiping all dishes with paper towels before washing, using a fine mesh screen in the sinks and shower, using Dawn dish soap for its grease cutting power, never dumping coffee, soda or anything else other than water into the sink, and any greasy dishes get washed separately outside.

Some RVs have a vent valve under the sink that can intermittently stick open or closed. It looks like a drain pipe that is capped off. The valve is in the "cap". I am told it is easy to replace but have never (yet) had to replace mine.

Again, if you've already tried all of this, then I have no other suggestions. Good luck!

 

[Spirituallifetime]

I would remove the tank and toilet and put in a composting toilet from Nature's Head. It separates the pee and poo to reduce any smells and also has a 12v fan that vents outside.
http://www.natureshead.net
Putting this toilet in will keep your class B sellable if you want to sell it in the future. Not many people will want an rv without a useable toilet!

Your tank may have build up wast  in it, once it has dried out it is like a rock and will not come out no mater how much water you put in the tank.

 

[cherterr]

I had this problem for a couple of weeks (or so I THOUGHT). However, in my 5th wheel, I DO use both tanks regularly; but my GREY water is open to a drain. EXCEPT for the time I accidentally closed it and my grey water tank filled up. And YES, it smelled exactly like ..ewww.. whatever (perhaps more moldy; but- ANYWAY, I opened it, drained it, used a little baking soda (which did NOT work when tank was full on this occasion), and all was well.

I'm sure by now you've straightened out you problem, but just thought I'd post for others, in the event.

 

[mockturtle]

Grey water is often the culprit.  Food particles, etc. can get really ripe, especially in warm weather.

 

[skyl4rk]

It is important to never let a black water tank dry out. I would keep it about quarter to half full of water if you don't use it (above freezing temperatures). You can just pour pails of water down the toilet, or use a hose.

 

[Suanne]

If there are resistant smelly bits stuck in the tank, fill it up with water and crushed ice (as a gentle abrasive). The ice will "scrub" the tank while you drive around for a while. Just wait for the ice to melt, then rinse well and empty.