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Bad Odor Coming From My RV's Bathroom Sink Cabinet

by Ann
(Lenhartsville, PA)

Bad Odor Coming From My RV's Bathroom Sink Cabinet

Bad Odor Coming From My RV's Bathroom Sink Cabinet

Bad Odor Coming From My RV's Bathroom Sink Cabinet
Bad Odor Coming From My RV's Bathroom Sink Cabinet

I have a odor in my bathroom sink in my 5th Wheel. When you open the cabinet under the sink the smell is bad. I don't know what could be causing it.

The 5th wheel is always parked in the same spot. I cant seem to figure out why only under the sink in the bathroom would be this smell.

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ANSWER: Hi Ann thanks for submitting your question on our Ask An RV Question Page.

There could be a couple of things that are causing your odorous problem under your RV's Bathroom sink.

My first and best guess is that you have a bad Air Admittance Valve (pictured at the top of this page). Some RV manufacturers use Air Admittance Valves under sinks in place of having a roof vent for the sink.

When you drain water out of your RV's sink the draining water creates suction (vacuum effect) on the valve which then opens and allows air in the pipe which in turn allows the water to drain freely into the holding tank. When the water is done draining the valve is suppose to close tightly and seal out any sewer smell or in your case gray water tank smell from coming in the RV.

Based on your description it sounds like your valve is not sealing properly and may need to be replaced. Replacing this valve is fairly simple in that in most cases the valve just screws onto the pipe. All you will need is a big pair of slip joint pliers to help unscrew your existing vent. To install it all you do is put some Teflon Plumbing Tape on the threads of the new valve and tightly screw it on.

The odor you are smelling from the gray water tank is usually from decaying food particles in the gray water itself. You might want to also start using some Enzyme Holding Tank Treatment in both your grey and black water tanks. The enzymes in these treatments digest waste and work quite well to minimize holding tank odors as well as being environmentally friendly.

Another cause could be that if you do have a roof vent on the top of the roof for your RV's bathroom sink the vent pipe leading up to the roof has a crack in it allowing fumes from the holding tank to escape under the sink, or the roof vent is blocked by a birds nest, wasp nest, etc. and is not allowing the fumes to escape.

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Lastly, you could have had a little varmint like a mouse or rat that has crawled under your bathroom sink cabinet and died.

I hope this information helps.

Do you have any suggestions or comments on this topic? You can add them to this page by clicking on the "Click Here To Post Comments" link located near the bottom of this page.

Happy RVing

RVing Al

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Comments for Bad Odor Coming From My RV's Bathroom Sink Cabinet

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Sink smell
by: Anonymous

I have found that the pipes themselves will get sludgy and need a good cleaning.

by: Kim

Hello we have a 44 foot camper that we live in and it is hooked up to city water and a septic tank in the last few weeks we have noticed a very bad smell coming from the drain of the shower what can we do to fix the smell .

Smell under sinks
by: Dave

I found my RV smell to be coming from a small leak in my kitchen tank. The over flowing used water was laying trapped on the protective cover under the RV. I discovered the leak when I lowered the protective cover to look for something else and the stinky sludge spilled out. I fixed the leak, cleaned then reinstalled the protective cover. Smell is GONE!!

Smell under the Sink
by: Brian

Install on of these, as I have, and you will eliminate the smell.

HepvO waterless RV Sink Trap

sewer smell
by: Anonymous

I have sewer smell coming out of the drains in my tub and in the bath. I have a separate tank for he kitchen sink.
I looked at the roof vents they look clear, I also took off the pee traps also clean I took off the vent under the sink and the valve also seems to be ok
the odor only comes up when you turn on the water
hope you can help

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