Toilet Stinks

[STJ]

We are having problems with the black tank smelling after a few days. We flush at the end of every trip, and every time are are at full hook up.
We have been use in the orange Campo pods and have tried others, but after a few days it starts to smell. This problem just started a few months ago, for the first 2 or so years on our 2019 Outback no problems. Do any of the others brands work any better, or even the liquids treatments?

[Balvar24]

I assume you mean that the toilet is smelling inside the camper while you're using it?

Are you keeping water on-top of the valve? If so, you may have an installation issue where the toilet joints to the floor/black tank.

[STJ]

Inside smell and yes keeping water on top of the valve only smells when we flush

[skids]

Originally Posted by Balvar24

I assume you mean that the toilet is smelling inside the camper while you're using it? (snip)

Now THAT is funny

[keyholeelf]

Don't run the fan when flushing. It pulls the smell in. I still forget to turn the fan off sometimes, just so my DW will start yelling.

[STJ]

Good advice but the fan is not on

[JRTJH]

First, what brand and model toilet do you have?

Thetford toilets are prone to leak at the bowl gasket.

Dometic 300 toilets are prone to leak at the bowl/base seal (factory seal not normally replaceable by users).

Dometic 310 and 320 toilets can sometimes leak at the bowl gasket. If the toilet won't hold water in the bowl, suspect this gasket is not properly seated.

Now, as for toilet smells. Many people turn on the vent fan when they start their "process" and leave it running after they are finished, so the smell can completley be drawn out of the trailer. Turning on the vent fan creates a vacuum in the bathroom and when you open the toilet ball valve to flush, you pull black tank odors through the roof vent and up into the bathroom through the open valve. So, always turn off the vent when you flush and then turn it back on.

Sometimes, if the wind is blowing the "wrong direction" you can open the roof vent and the wind blowing across the trailer roof will pull odors up through the vent stack and then push them down the open roof vent (if the fan is turned off). So either way, there's a possibility of black tank odor coming into the bathroom via the toilet/vent fan or via the vent stack/vent fan opening....

As for chemical treatment, there are several that people use. Ask anyone what works and they'll tell you the one they use is "the ONLY one that works"... Honestly, if the toilet is functioning properly, the vent stack is functioning properly, the vent fan is used correctly AND the wind is blowing in the advantageous direction, there's really no "stink from the tank".....

A couple other things you mentioned that you might want to take a look at:

You said you always dump the tank at the end of every trip and every time you're connected to full hookups... You may be empting the tank too frequently. If the tank isn't full, there won't be enough "rush of water" to draw the solids off the tank bottom. So never dump a half full tank. If you are leaving the campground and need to dump, then ALWAYS fill the black tank completely (even if it means standing at the toilet, filling the bowl repeatedly until the toilet "burps and gurgles)... That will help you get all the solids out of the tank...

If you're at a full hookup site, consider filling the black tank, dumping the contents, then with the dump valve open, connect the black tank flush and let it run for some time.... An hour may seem like a long, LONG time, but if you check and there's still "brown bits" (often called "sewer trout") then there's still "smell in the tank as well as the fish".... Keep flushing.

I think that if you always start with a relatively clean (not just empty) black tank, turn off the roof vent fan before flushing, leave the roof vent closed between uses if possible and make sure the toilet is in "working condition without the above issues" you should be able to eliminate most of your black tank odor problems.

It's not really about what brand "odor mask" you buy, it's more about having a tank that doesn't emit so much odor the mask can't possibly keep up with the job.....

[German Shepherd Guy]

Hello STJ.


I noticed you said for the first couple of years there was no smell


I also noticed you said always parked in a campground with full hookups.
AND that you did use the Black Tank flush regularly.


So, question, when hooked up to the to the septic system in the parks did you 1) have the black tank open all the time or 2) did you just open it when the tank was full and then flush it and then shut it again?
Reason I am asking is it sounds like you might have the dreaded "poop pyramid" from using the 1st method



IF you always opened the tank then even using the Black Tank Flush the trailer comes with will not wash away the solids and they will accumulate over time.

IF that is the case you will need to do some remedial work. You could try filling the black tank 3/4 full with water and some dish soap when you depart one campground for another, and letting the towing act as the agitator to help clean out the tank. Empty first thing at the new campground and then close it up and only empty it when it is full, even though you have full hookups. Also flush with ample amounts of water.



Some poop pyramids turn into a type of concrete the Romans would have been proud to build with and so that may not do it.
Hope for the best,
Good Luck

[bsmith0404]

You’d be surprised how much stuff is still in the tank after using the black tank flush. If you have somewhere that you can connect to sewer and give the black tank a good cleaning, you might be able to get rid of the smell. You can get the sewer connection that allows you to spray water back in from the outlet, also some of the wands you put down through the toilet work well. Fill you black tank 2/3 full with water and dump several times to get powerful flow. I’ve “cleaned” several black tanks where people always use the black tank flush.

[STJ]

Sorry for the confusing we do stay at full hookup parks but when we do we never leave the black tank open, and the smell only happens when the flush valve is open, when closed it’s fine.
After reading some of the comments I am thinking the black tank vent could be clogged , although when I dump I don’t seem to get any vacuum stoppage with the toilet closed as it always is.

[bobbecky]

You might try one of the enzyme type tank treatments. We converted a number of years ago and have had much better results. With two of us, I normally dump the black tank once a week, but it’s about 50 gallons, so a smaller tank might need dumping a couple times a week.

[Ron]

Originally Posted by bobbecky

You might try one of the enzyme type tank treatments. We converted a number of years ago and have had much better results. With two of us, I normally dump the black tank once a week, but it’s about 50 gallons, so a smaller tank might need dumping a couple times a week.

I was going to mention the vent possible plugged, while flushing the toilet and you get a blurp of air back at you, yes the vent is plugged or tank is getting full....

[bsmith0404]

Originally Posted by STJ

Sorry for the confusing we do stay at full hookup parks but when we do we never leave the black tank open, and the smell only happens when the flush valve is open, when closed it’s fine.
After reading some of the comments I am thinking the black tank vent could be clogged , although when I dump I don’t seem to get any vacuum stoppage with the toilet closed as it always is.

Do you put a p trap in your sewer hose? Basically just have a low spot where it dips and can fill with water. Same concept as any p trap, prevents the sewer gases from flowing back into your RV.

[dutchmensport]

There's only one reason why your tanks smells. It's because it's not flushed out and "stuff" is still hanging on. (Literally). Your tank need a good cleaning, and the only way to do that is to flush it.

Ideally, you should drain your black tank completely. Then add about 5 gallons of water, some Dawn Dishwashing Liquid or any kind of laundry detergent and then take the camper on the road for a while. When you reach your destination, dump the tank. The sloshing when driving will clean things up. A little bit of bleach goes a LONG way in getting rid of smells. Just be sure to flush the bleach water as soon as you can from the tank.

Another trick you can do, which is what I do every time I dump my black tank, and that is to back flush the grey tank water into the black tank. This only works if your black and gray tank outlets discharge through the same outlet. You need to attach a 3rd valve on the outlet, like a Flush King. The process is simple. Drain the black tank until it quits running. Close the Flush King valve and now open the grey water valve. This causes the grey water to flush backwards into the black tank. The backward flow of the water will help break down anything still "hanging on." When the two tanks equalize, close the grey water tank valve, and now open the Flush King again and drain the black again. You can repeat this 3 or 4 times depending upon how much grey water you have in your tank. Like I said, I do this EVERY time I dump my black tank.

Another thing you can do to help clean the tank out, is to catch your dish washing water in a pan. And rather than dumping it down the sink, dump it down the toilet. The soap water will help clean things up a lot more, and also reduce smells.

I never use any kind of RV chemicals in any of my tanks. Back flushing works about 90% of the time. For the other 10%, I always add about 5 gallons when traveling. Once a year, I may add bleach and go for that drive between campsites. And no, doing all of this, I never have to use the built in black tank flusher. Also, my sensors always work, and I almost never have smells. When we notice "the" smell, we add dishwashing water. We also have a washing machine that drains into the gray tank. The laundry soap back flushing also keep the tank odor free. And actually.... thinking about it ... since we got the washing machine (over 1 year now) ... um ... we've not had any black tank smells at all! The back flushing with the Laundry water is doing pretty darn good.

No RV black tank chemicals. Save your money.

[Crossfired]

Between uses fill the tank half full with water and little borax then drive around for 15 or 20 minutes then dump. Rinse out if you have the fitting. Bonus points if you do it twice. If you do that fairly frequently she stays mostly odor-free and clean.

[STJ]

All this sounds great about dawn flush might be nice. We are camping now headed home tomorrow will look into the clogged vent then on to the dawn clean out. Next trip is in 2 weeks.
Thanks, Jeff I will send an update

[NH_Bulldog]

I have never used any chemicals in the black tank, only the grey tank. With all the stuff that ends up going down the sink and shower drains, the grey tank is just nasty and a chem pod seems to fix the issue.

This is not to say my s**t doesn’t stink, but the black tank has a flush system that I use very regularly and there is no smell and the gauges are always right on. A 5 minute flush won’t cut it, you need at least 10-15 minutes to get the job done. I would suggest some good soapy water in there, head out on the road to stir it up and then drain and flush again.

[Weldon]

https://www.trbowlin.com/bio-geo-method/

This worked for us. Borax, zep, and water

[STJ]

Latest update: Black tank vent is open aka not clogged and venting like it should be, that would have been too easy. Next trip I will do a good flash and maybe try the bio method Weldon recommended. Updates to come.
Thank, Jeff

[STJ]

Weldon are you using the borax and dawn every time you dump like pods or just when it needs a good cleaning.
I think i will try this.