Gray Tank Odor in Kitchen

[Ntense0911]

Hey all,
I've been looking through a bunch of different threads and havent found exactly what I'm looking for. I have a 2017 Front Kitchen Montana and over the past couple of weeks a TERRIBLE gray tank odor has greeted me when I come home from work. Ive dumped tanks, I use Unique Tank treatment. I dont have a vent valve under the sink, the vent goes up through the roof. I have not seen/noticed any leaks.....any suggestions?

Ronny

[Kyle and Lisa]

Make sure all valves are closed at all times until you are ready to drain a specific tank.

[Ntense0911]

Thanks, I do indeed keep them shut until dump time.

[RMcNeal]

You might try back flushing the kitchen gray tank using a Flush King valve on your sewer outlet. You can close off and back fill the tank with water and then flush several times to remove any food particles and such.
You might also consider getting a hose meter to better control how much water you back fill into the tank. Counting and timing is unreliable as the volume and pressure varies wildly from place to place.

https://www.amazon.com/Valterra-Degr...zcF9hdGY&psc=1

https://www.amazon.com/Save-a-Drop-P...64&sr=8-6&th=1

[twindman]

I think I remember someone talking about the roof vent being plugged and causing this problem. Can't remember the details tho.

[Ntense0911]

Thanks all!

[daboom11]

I've had pretty good luck washing my coffee grounds down the sink.

[ReneT]

Did you check the air admittance valve under your kitchen sink. The valve opens when you drain the sink allowing water to enter the piping when draining the sink. Without it, you would suck all the water from the sink trap.
After the draining stops, the valve shuts keeping the smell in the piping. Your’s may not be shutting all the way. Locate it and tape a ziplock bag over the valve and see if the smell goes away

[Jay Merritt]

Replace this under the kitchen sink. To verify this is the problem, place a zip lock bag over the top, and use a rubber band to seal the bottom of the bag to keep air from leaking.

https://www.amazon.com/gp/product/B000KKSP52

[ReneT]

Originally Posted by Jay Merritt

Replace this under the kitchen sink. To verify this is the problem, place a zip lock bag over the top, and use a rubber band to seal the bottom of the bag to keep air from leaking.

https://www.amazon.com/gp/product/B000KKSP52

That’s what I just said in post #8,

[DutchmenSport]

Originally Posted by ReneT

Did you check the air admittance valve under your kitchen sink. ..

The OP said he does not have the Air Admittance Valve under the sink. His kitchen grey tank is vented on the roof.

For the OP..... check on your roof and see how close your kitchen exhaust fan is located to the grey tank vent on the roof. If they are within close proximity of each other, it's possible the odor is escaping the roof vent, but being sucked right back into the camper from the exhaust ceiling fan. When the wind blows just the right direction, odors come back into the camper. It does happen.

[ReneT]

Originally Posted by DutchmenSport

The OP said he does not have the Air Admittance Valve under the sink. His kitchen grey tank is vented on the roof.

For the OP..... check on your roof and see how close your kitchen exhaust fan is located to the grey tank vent on the roof. If they are within close proximity of each other, it's possible the odor is escaping the roof vent, but being sucked right back into the camper from the exhaust ceiling fan. When the wind blows just the right direction, odors come back into the camper. It does happen.

The vent pipe he’s talking about may be a vent for one of his waste tanks. Could be black or gray.

I hope he still looks under his sink counter for an air admittance valve. The tank vent is not what allows the sink water to drain properly/quickly and not suck out the water from the sink trap. A air admittance valve does. Unless the vent pipe is install in the sink drain piping and close to the sink. If it goes directly into the tank, then the sink should have a air admittance valve

[DutchmenSport]

Originally Posted by ReneT

The vent pipe he’s talking about may be a vent for one of his waste tanks. Could be black or gray.

I hope he still looks under his sink counter for an air admittance valve. The tank vent is not what allows the sink water to drain properly/quickly and not suck out the water from the sink trap. A air admittance valve does. Unless the vent pipe is install in the sink drain piping and close to the sink. If it goes directly into the tank, then the sink should have a air admittance valve

You made me look under my own kitchen sink out of curiosity because I did not remember the air admittance valve under there. And sure enough, my MHC does not have one. I found a photo in my library of my pipes when I added an outside shower, it was the best I had showing the plumbing of the black ABS pipe. It's attached below.

It shows the ABS black pipe drain coming down from the sink, the P-trap, and finally the turn going down into the floor and into the grey holding tank. Notice the top of the pipe... it goes up. That's my vent going to the roof.

On this end of the camper there is only 1 vent on the roof. I imagine, that black pipe that goes up also has a Y in it, somewhere in the wall. The other half of that Y would be the vent for the gray tank. So, both kitchen sink (air admittance) and black tank share the same roof vent.

So, not every camper has the air admittance valve under the kitchen sink.

[ReneT]

Thank you for the update. Hope you have a very Merry Christmas

[Kfinnert]

Odors in the kitchen can be caused by all of the comments herein. Two additional thoughts, ensure you have water in the P-trap and check the vent pipe on the roof.

Regarding the vent pipe. If you are stationary for any length of time, insects can/will build a nest or spiders will spin a web across the opening. Overtime, that insignificant "web" will collect moisture and dust and block the vent. A quick sweep with a broom handle down the pipe will clear that out.

Okay, one last thought. Do you have the traditional sink drain or the waterless RV sink trap. If you have this type of trap, then the baffle within the drain could have debris within it that keeps the trap open and permits the odors to creep in. It just needs to be cleared. There are several posts on how to manage the clearing of the blockage, but it is easy.

Cheers