Does your bathroom stink?

[vacuumbed]

In my 2005 Concourse the bathroom always has this grey water smell. Are other units like this?

[Blue~Go]

Maybe. Reason I say that is that I started noticing that sometimes when I drive, greywater smell comes in through the shower drain. Obviously this has something to do with the trap, because greywater/tanks always smell awful, but the water in the trap "seals" this off from the interior. At first I thought it was because the grey water had been fairly full, and I had driven down a hill to the dump station. Or that perhaps the shower trap water had evaporated, because I'd been camping in a place where I had access to a shower and had not been using the Chinook shower. I added water (and kept traveling - I was on the road) but that didn't totally cure it.

Next, I feared the worst, which I define as the trap or pipes leading to it cracking (because what a nightmare to get to to repair!). But I could see the trap (from outside by the steps looking toward it), and after filling it with water from inside.... no leakage.

I also then noticed that it didn't do it at all when I was parked/camped, even when there was certainly grey water in the tank. But then it did it again when I was on the road.

So my latest theory is that since my Concourse is fairly light and "perky" in back (i.e. rear of coach is higher than front), that perhaps when I drive the up/down bouncing that is inevitable in back, is somehow causing the trap to empty/siphon into the grey tank. And then of course smell comes up, as that's what water in the trap prevents. It IS fairly low and close to the tank as compared to any of the other traps.

[vacuumbed]

Mine has a strange odor all of the time, even when pared for a week. So yours does too? Thanks for your help.

[Manitou]

Does water stay in the bowl of the toilet? My seal has been shot since I got the RV. Need to get that replaced some day (I don't want to do it personally).

[Blue~Go]

Good point on the toilet.

In my rig it is only the shower drain that emits grey tank odor, and it's only when traveling. I think the shower drain trap is emptying itself through a combination of bouncing and siphoning. I re-fill the trap when I stop and all is fine again.

But if it's the bathroom in general, you have three possible sources:

1) Shower drain trap (prevents grey tank odors from coming in shower drain).

2) Bathroom sink trap (prevents grey tank odors from coming in sink drain).

3) Water staying constantly in toilet bowl. Since the toilet has to trap, but simply dumps straight into the black tank (typical in RV's), the "trap" is the fact that water remains in the bottom of the bowl at all times. A seal keeps the water from draining. If the seal is faulty, and water doesn't stay in the bowl, you essentially have a black tank venting into your bathroom.

So basically grey and black tanks always smell horrible. Just like in your home the sewer system smells horrible. BUT, traps (full of water) keep the smell from coming in, so you don't ever have to smell it. (I mention this as sometimes people think this means they need to keep their grey/black tank from smelling, when actually the key is to keep that smell out of the living space).

The toilet seal is a notorious one, and when it fails water doesn't stay in the bowl, and you can smell the black tank (but not the grey tank).

As long as we are on the topic, although this is the kitchen not the bathroom: The kitchen sink is not vented in the traditional way. It uses an Air Admittance Valve (AAV). The kitchen sink DOES have a trap, and water in the trap keeps odors from coming up via the sink drains. But the kitchen sink doesn't have a normal vent. The vent is necessary to let air in as the water goes down the drain. Without it you'd have "burping" as you drained water. Running a traditional vent over to the vent stack wasn't done, and instead an AAV was used. The type used is a one-way valve with spring that reacts to pressure differential. When working properly, it lets air in as water is draining, but doesn't let air out at other times (which would be sewer air).

During my remodeling project, I found that the AAV was only hanging on by a hair (it's screwed in place), and was on the verge of totally letting sewer gas into the rig (although it had not as of yet). The threads were gunky.

I replaced it with a slightly more expensive design that is a little less "mechanical." When I say more expensive, it was $19 vs. $6.

Anyway, if you get gurgling when you try to drain kitchen sink water, or sewer smell under the sink counter, you might check the AAV. Mine was located just below the sink counter in the rear/outboard corner. You can see it sticking up from the drain line downstream of the sink, like a little black hat.

[Blue~Go]

I think I may have tracked down the "other half" of my smell issue.

To re-cap, I would get a "tank smell" when driving. I noticed it was coming from the shower drain. I'm still not sure exactly what is happening, but I think that because the shower trap is so close to the level of the grey tank (low), and because it's right at the rear of the coach, and because it can be a bit bouncy back there (especially on not-so-velvety roads) -- that as the coach bounces shower trap water is mixing with grey water from the tank. So then the trap is filled with grey water and of course that no longer seals out odors since it smells itself. (Until I put enough water down it to cause the trap to be full of fresh water again.)

I solved that (at least for now) by sealing off the shower drain while I'm driving. Then make sure trap has new fresh water in it when camping/using shower.

But then I noticed I STILL had a tank odor in the bathroom either during a strong wind, or when driving if I open my window (creates negative pressure). It wasn't coming from the shower drain (had it blocked off to be absolutely sure, plus putting nose near it there was no smell). Or from the bathroom or kitchen sink drains - their traps were working perfectly, as was the new AAV I put in on the sink line. So no issues there. And there was water held in the toilet bowl, so it couldn't be that..... or could it? Yes, there WAS a grey water smell coming from the toilet bowl. What that...??

Then I noticed two triangular drain holes up near the rim. Well, gee, so much for water in the bowl when the drain holes lead right to the black tank. Did a bit of research and apparently up to the year 2000, overflow drains were required for RV toilets. And they BYPASS the water in the bowl and go to the black tank (via the drain). That explains that! What a goofball design. As an experiment I taped over the vents partway through a drive and, Voila, no smell.

Doing some reading it seems that some people just buy the seal kit that does not have the hole punched for the drains (i.e. newer seal kit for same toilet), and that solves the problem. Of course then if you have an overflow there would be an issue, but I'll trade that for constant smell in wind or when driving. I mean, I'm standing right there when flushing, and worst-case scenario I could reach down and close the toilet water shutoff valve.

I did read one Amazon reviewer who said that this caused water to leak out around the bottom of the bowl in normal operation (no overflow occurred); but I can only think that this person used a spray wand and thus sprayed water into the overflow holes and then it had no place to go so leaked out.

I guess another way would be to seal off the overflow holes in the bowl itself.

Or get a new toilet without them.

Anyway, I was sure glad to finally figure that out! I mean, come on, it should be simple. Water in traps (toilet bowl serves as a trap) and you could have tanks full of rotting skunks and there should be no smell! Smell can't get through water.

[Skillet]

Wow, good sleuthing! That was a good read.

[Blue~Go]

Ha, never thought I would be "entertaining" folks with tales of tracking down holding tank smells

[Blue~Go]

Just a follow up. Drove around 500 miles since blocking off the toilet "vents" and no more smell, even with the driver's window down (which creates negative pressure and always made it worse).

Silly design, but since I'm not going to immediately replace the toilet, I'm going to instead use the metal duct tape (the stuff that is actual silvery metal tape) to block them off. It's thin, fairly high quality, and will block any odors completely. I'll just replace it when necessary. Yes, kind of dumb, but then any new toilet won't have the vents (apparently they were eliminated around year 2000).

If you are wondering if you have these, mine are up "under the rim" on each side between the middle and rear of the bowl, and are sort of triangular shaped. If you are looking down at the toilet, and it's a clock, they are at around 10 p.m. and 2 a.m.

[Astrodokk]

Good to know. I have that metallic tape (used for furnaces) and I will be plugging mine up soon. I have had that certain odor as well and couldn't put my finger on it.
Now I can, covering those drain/vent holes with that tape.
By the way, mine are at 10 a.m. and 2 p.m.