Hello. We have a three month old fifth wheel with a new issue that just started two weeks ago under the very specific following conditions (that happen to occur often). When the grey tank is more than half full, somebody is taking a shower and the grey holding tank valve is closed. A very strong odor enters the master bedroom. The smell is nasty, but hard to describe. Not really sewage, not really gas, but sort of like something in between perhaps. The smell is not detected in the bathroom or anywhere else in the unit, only in the bedroom which is next to the shower. FYI. We have two grey tanks and the one serving the shower only serves it and the bathroom sink. If I open the grey valve and drain that grey tank before the shower or leave it open or it is less than half full during the shower the odor is not detected at all. Also, the odor only fills up the bedroom during the shower and for approximately 15 minutes after the shower, then it goes away. I tried several grey tank odor cleaning priducts, but they have had no impact either. I have not detected any obvious signs if leaks either. We are new to this, but learning from experienced people like yourselves. Thank you.

Look to see if you have a vent on the roof. You could have a vent under the sink or in a closet for venting the shower grey tank. It could have problems. If vented through roof, this is not the problem.

Check the air admittance valve that is likely located under the bathroom sink. If this fails to close properly it will let odors from the grey tank enter the living space. This is a vry inexpensive device available from any home improvement store for $10 or less.

Hummm... he said the odor is only in the bedroom. If the air admittance valve under the bathroom sink were to malfunction....wouldn't the odor then be only in the bathroom?Sounds to me like the vent tube that goes to the roof is in the wall between the shower and bedroom and has somehow separated from the tank or maybe a connector on the tube has separated and allowing odor to penetrate the bedroom wall.Anyway, that's my best guess and where I would start looking. However, just to make sure, I would definitely check the air admittance valve just to eliminate that possibility.Ron

I agree with ron. your vent tube seems to have separated in the wall

Others are likely correct but as Ann alternative: check your battery. Feel the sides to see if it is hot or quite warm. Internal short will cause off gassing a sulfur dioxide gas. If it's hot get it disconnected and take it for testing at most any auto parts store or battery retailer. It's possible for them to explode if left in service and there is a short.

new strong odor - help/advice please | Good Sam Community

sandyhillbill
Explorer
Nov 06, 2013
My guess is the vent pipe was either installed too deep in the grey tank or has slipped down into the tank.
3_dog_nights
Explorer
Nov 06, 2013
Battery / Shower connection? are you using the gas or the elec for heating the water? If elec, try gas only, still smells? if not, look at the battery idea.
if so, keep following the vent pipe leads.
captbobny
Explorer
Nov 05, 2013
I also think that this is caused by the hot water heater.
pointrow
Explorer
Nov 05, 2013
Just a wag but does your water heater have an sacrificial aneroid? They can smell just like you describe and could be source of smell during a shower.

Smells can be a stinker to track down!

good luck
pointrow
hittingtheroada
Explorer
Nov 05, 2013
Our 5th wheel had a strong smell when using the shower with the exhaust fan on. Turns out the vent pipe was not seated all the way in the cap on the roof. I sealed it with some putty and the odor stopped.
bad99ram
Explorer
Nov 04, 2013
On my washer dryer prep there is a air admittance valve near the washer P Trap. That would let odor in the bedroom area.
tvman44
Explorer
Nov 04, 2013
X2, smell under the bathroom sink if it smells there you need a new air admittance valve aka vacuum breaker.

wborst wrote:
Check the air admittance valve that is likely located under the bathroom sink. If this fails to close properly it will let odors from the grey tank enter the living space. This is a vry inexpensive device available from any home improvement store for $10 or less.
weberchk
Explorer
Nov 04, 2013
This is all helpful. Question. Would battery overcharging have any correlation to showering? That is the only time it occurs.
Old-Biscuit
Explorer III
Nov 04, 2013
sljkansas wrote:
I wonder if the problem is the vent pipe is too low in the gray tank, and when half full the vent pipe is full of water, which would cause the odor to build up and then release when the water is flowing in the trap.

Very good possibility......

IF vent line is getting blocked the fumes have to go somewhere when additional water is added to grey tank as could flow back up shower drain as it is being used.
Then smell goes away when grey tank is drained.....vent pipe no longer under water/blocked.

The other possibility is the battery off gassing from overcharging.
Easy to eliminate...check battery water level, any bulging of battery case and if the case is hot.

If battery checks good..........then that vent pipe is suspect.
The vent line problem will need to be corrected. Line slipped down into tank to far.......dealer fix as it might need to have tank removed to reposition & properly secure vent line.
sljkansas
Explorer
Nov 04, 2013
I wonder if the problem is the vent pipe is too low in the gray tank, and when half full the vent pipe is full of water, which would cause the odor to build up and then release when the water is flowing in the trap.

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new strong odor - help/advice please

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