Bathroom smell after emptying tanks

[Jason.rhodes86]

On week vacation. Emptied tanks Tuesday and then yesterday, Thursday. After doing it yesterday the bathroom has smelled pretty bad, like a porta potty. The seal on the flapper is fine because it’s holding water in between uses. Could just need another dump with a good flush out or two? Any ideas?

[Canonman]

I'd bet a good flush out would help. If your trailer is equipped with a black tank rinse, use it. If not you'll need to fill the tank with a hose or just standing on the flush valve until full. Then drain and repeat. Twice if it's not too inconvenient.
Add a cup of detergent and if you have any, a cup water softener like Borax. Then fill the tank about 1/2 to 1/3. Let that stand until you need to dump again. Even better if you need to travel and have it "slosh" around for a few miles. Once the tank is clean you can reduce the water with soap and Borax to just a couple of gallons.
A lot of folks use the chemical additives like "Happy Camper". There are several brands on the market, but we've had really good luck with the "Bio-Method" described at the beginning.
The best way to tell if you have a clean tank, is to shut the bathroom door, turn on the overhead fan, open the toilet valve and wait for the truth to reveal itself

[Jason.rhodes86]

I do use chemical additive I put down the toilet on arrival. We’ve never had an issue until now. We leave tomorrow so I’ll dump and use the black tank flush and hopefully that works. Probably won’t know until we camp next but I can’t think of anything else that would cause it. Just weird we’ve never had an issue until this last tank dump.

[chuckster57]

If your using the gel packs, I can tell you from experience they DONT dissolve and release the chemicals. I use TST citrus.

[Canonman]

It was explained to me that the black tank is like an enclosed toilet bowl. Sometimes you need to flush more than once
Try the double flush and bio method. Then test when you get home with the fan on and flapper open.

[Jason.rhodes86]

I do use gel pacs but they always dissolve easy when I’ve used on gray tank setting on drain and running water. Plus when I drain water is always blue.

I went ahead and drained black tank and used the flush for a good 5-10 minutes after and then drained the rear gray tank so we’ll see if it helps before we leave tomorrow.

[jsb5717]

Originally Posted by chuckster57

If your using the gel packs, I can tell you from experience they DONT dissolve and release the chemicals. I use TST citrus.

^^^Ditto this. Whenever I've had that stinky scenario I've used a 5 gallon bucket to pour 8-10 gallons of water into the toilet. Then I drop in a couple of the TST packets. Then just use the toilet as usual until the next time to dump.

It's possible that you're dumping it too often, that is if you're in one spot for more than a couple days. IMHO, the real solution to getting the tank to empty well is A LOT of water. You might be dumping your black tank without enough to do the job well. Even after just a weekend of camping make sure there is plenty of water before dumping.

Personally, I don't use the rinse connection. If there's enough water in the tank before dumping you'll never need it.

[bobbecky]

We are fortunate that our rig has a 50 gallon black tank and with it, we can last at least a week between draining. Not knowing what model and year your rig is makes it hard to guess what your capacities are, but even if your black tank is only 30 gallons, you should be able to last four or five days unless there are more than two of you in the rig. A full or close to full tank is really the key to a happy black tank. And if you are traveling, it is not necessary to drain each day, better to drain on a schedule and let the tank contents slosh while moving which will aid the health of the tank and make for a better drain.

[dutchmensport]

If your black tank and your grey tank both empty at the same port, then attach a Flush King type valve on the end and back flush the grey water into the black tank. It saves water, you re-use the grey water, and it cleans out all the stuff that simply dumping leaves behind. You do not have to add water through the toilet bowl to flush the tank, using even more water, if you do it this way.

Doing this every time you dump the black tank, and your black tank's smells will be greatly reduced! Add a bit of Dawn dishwashing liquid or some liquid Tide laundry detergent when you are done. That can stay there until you do your next dump. Tanks won't smell.

[hankpage]

Another thing>>> If your roof vent is open when you dump you can get smell back in from the black tank vent on the roof depending on wind direction.

[Jason.rhodes86]

Dumped this morning and flushed good before leaving. Got home and smell is still there. Since the smell is getting there from the tank, I guess next I’ll look into the wax seal under the toilet or the ventilation system. Only way I can think smell is getting in. Never had this issue untik this week.

[slow]

What toilet brand and model do you have?

The Dometic 300 has a known sealing issue between the bowl and base that eventually results in sewage smell.

Google “Dometic 300 problem” for more info.

Dometic may still be replacing them free of charge.

[Jason.rhodes86]

Great info I will check to see if that’s the toilet I have

[travelin texans]

I've had Dometic & Thetford toilets neither have wax rings under them but rather rubber gaskets.

[jsb5717]

It doesn't sound to me that the OP has thoroughly flushed the tank. If there is lingering sewer odor then there is likely still some old poo poo pile in there. 10-15 gallons of water with the TST packets should be put in there right away. Just leave it sit like that for a few days. Then take it on a drive to give it a good slosh. Then fill the tank to over half full and dump. Repeat as necessary. I've had some pretty stinky tanks but after a good, thorough flush the smell goes away.

If there is any residual smell leaking up through the toilet then it's more likely the flap seal, not the floor mount seal. Is it possible that the tank itself has some kind of breach above the water line?

[bobbecky]

RV toilets can not use wax seals as they will melt when it gets hot in the rig, that’s why they only use the foam rubber seals.

[RickV]

The Grey water tank can get pretty nasty smelling too, are you sure it is actually the black tank? On our old 5th Wheel we would notice after traveling there would be a nasty odor in the 5ver. We started driving with roof vent open and it helped. Eventually I figured out it was the RV sink vent valve malfunctioning because of the cheap valve that was installed at the factory. I replaced it a quality one and the problem was gone.

[Jason.rhodes86]

Ordered some tst. Gonna give that a try like suggested and see what happens. I’ll also check my toilet today I guess it’s possible I have one of the defective ones. We’ll see.

[Jason.rhodes86]

Originally Posted by slow

What toilet brand and model do you have?

The Dometic 300 has a known sealing issue between the bowl and base that eventually results in sewage smell.

Google “Dometic 300 problem” for more info.

Dometic may still be replacing them free of charge.

I do have this toilet. And when looking at it to find out and get serial number, I noticed a pretty good odor coming from the rear of the toilet. I’m guessing this is gonna be my issue which would make sense why I’ve never had a problem and then all of the sudden smell is there. I’m gonna call tomorrow to see if mine is covered under the warranty stuff and go from there.

[slow]

Originally Posted by Jason.rhodes86

I do have this toilet. And when looking at it to find out and get serial number, I noticed a pretty good odor coming from the rear of the toilet. I’m guessing this is gonna be my issue which would make sense why I’ve never had a problem and then all of the sudden smell is there. I’m gonna call tomorrow to see if mine is covered under the warranty stuff and go from there.

Hopefully it is as simple as changing out the toilet to resolve the smell issue. Good luck with the claim for free replacement.

If not covered by Dometic or if they are willing to let you top up, I suggest replacing your current toilet with the all ceramic 320. Since the 320 is a little longer front to back, check that you have enough clearance behind the toilet.