I love our travel trailer, but we have been having some serious issues with a very potent smell. Issue: Every time we run the kitchen faucet we get a rotten egg smell out of both of our A/C units almost instantly. We’ve had the unit for about 3 months, and this has been going on for about 2 months. Things I’ve tried: 1) Replaced the air admittance valves underneath both sinks. 2) Got on top of the unit to ensure the vents weren’t clogged, even ran water down them. 3) Cleaned gray tank, put tons of detergent, fragrances, and cleaning solutions in the gray tank to clean it. 4) Checked the anorod on the water heater5) Keep the gray tank closed until ready to empty6) Called the manufacture, they sent out a tech and were unable to find the problem. Have also called multiple service techs and no one seems to have heard of the issue. Does anyone else have any other ideas? We are seriously bummed about it, my wife and kids hate it. We love the unit except for this issue. Any help is appreciated!I have a 2022 Forest River Travel Trailer, Heritage Glen

Showing my ignorance: What is an air admittance valve?Try some of the same product you use in the black tank such as Campa Chem, Camco TST, etc. That type of stuff works in the black tank, and it also works in the gray tank.It's hot in Texas, and that makes the smell increase. I would think keeping the gray tank closed is the wrong way to address the problem.I suspect the odor is coming from the vent pipe on the roof, and being drawn into the A/C. You need to clean up the gray tank odor. Leave the valve open. Add some RV deodor product. Good luck.BTW, Gray tank water typically can smell worse than black tank water.

It's a one way valve to allow air into the drain pipes. You can see a picture of one at this link.https://www.homedepot.com/p/Oatey-1-1-2-in-ABS-In-Line-Cheater-Air-Admittance-Vent-39012/100204205#overlay

Generally there is a cap or housing on top of your roof that covers the vent pipe that protrudes through the roof. Maybe your cap or housing is damaged or missing.

It could be the water heater anode reacting to the water. This has happened to us a few timesbeginrv.com/rv-smells-like-rotten-eggsTry a zinc rodRead The Reviews

Gray Tank Smell (Seriously annoying) | Good Sam Community

wa8yxm
Explorer III
Jul 16, 2022
Question: Many advise that when you are on a full hook up site to close your black tank (And they explain the reason I won't here) but leave the gray open till you are getting ready to leave.

NO. Close both valves and dump when you have to.

Why?
Ever see the ads for the RV Black Tank treatments that basically are a waste of money.. A Stinky RV that everyone is avoiding?

Well the Stink is not coming from the holding tanks ..it's coming from the park's sewer system up the 3" hose and into the GRAY tank via the open valve.> Close the valve to block the stink..
Wulrich
Explorer
Jul 17, 2022
FIXED IT! There were one or two comments about the vent pipe not protruding high enough… after taking the vent cap off for the 5th time in the last several months, I noticed that it was under the roof line and that the hole that was cut out for the pipe was not done very well leaving large gaps of space between the roof and the pipe. I ripped the base of the vent cap out, and replaced the entire setup with a Cyclone https://www.homedepot.com/p/Camco-Cyclone-Plumbing-Vent-Black-40597/309587984?source=shoppingads&locale=en-US&&mtc=SHOPPING-BF-CDP-GGL-D25T-MULTI-NA-Multi-NA-SMART-NA-NA-NA-NA-NBR-NA-NA-NA-PortablePower_SmartShopping_HighOrganic&cm_mmc=SHOPPING-BF-CDP-GGL-D25T-MULTI-NA-Multi-NA-SMART-NA-NA-NA-NA-NBR-NA-NA-NA-PortablePower_SmartShopping_HighOrganic-71700000081625943-58700006942154417-92700062499001868&gbraid=0AAAAADq61UcTn6pCWXnwm7_gD2xgmJLE9&gbraid=0AAAAADq61UcTn6pCWXnwm7_gD2xgmJLE9&gclid=EAIaIQobChMIouHW_piA-QIVVMLCBB29kAGfEAQYAyABEgIO1fD_BwE&gclsrc=aw.ds#overlay) and it seems to be working just fine now, no smell!

Thanks everyone for the suggestions! My wife can finally be happy again!
ktmrfs
Explorer II
Jul 17, 2022
wa8yxm wrote:
Question: Many advise that when you are on a full hook up site to close your black tank (And they explain the reason I won't here) but leave the gray open till you are getting ready to leave.

NO. Close both valves and dump when you have to.

Why?
Ever see the ads for the RV Black Tank treatments that basically are a waste of money.. A Stinky RV that everyone is avoiding?

Well the Stink is not coming from the holding tanks ..it's coming from the park's sewer system up the 3" hose and into the GRAY tank via the open valve.> Close the valve to block the stink..

EXACTLY ON KEEPING VALVES CLOSED!!!! sewer lines doesn't have a P trap. I remember being at a park several years ago where one camper was complaining to the park about sewer smell at their sight. Cause.... dump valves open.

And a grey tank that is not occasionally cleaned can smell as bad or worse than a black tank. Occasionally before I dump I'll add some laundry detergent to the grey tanks, let it slosh around overnight then drain.
Itinerant1
Explorer
Jul 17, 2022
Excellent that you found the culprit. ;)
Rick_Jay
Explorer II
Jul 17, 2022
Glad to hear it! Thanks for posting your solution!!!!

~Rick
dougrainer
Nomad
Jul 18, 2022
ktmrfs wrote:
wa8yxm wrote:
Question: Many advise that when you are on a full hook up site to close your black tank (And they explain the reason I won't here) but leave the gray open till you are getting ready to leave.

NO. Close both valves and dump when you have to.

Why?
Ever see the ads for the RV Black Tank treatments that basically are a waste of money.. A Stinky RV that everyone is avoiding?

Well the Stink is not coming from the holding tanks ..it's coming from the park's sewer system up the 3" hose and into the GRAY tank via the open valve.> Close the valve to block the stink..

EXACTLY ON KEEPING VALVES CLOSED!!!! sewer lines doesn't have a P trap. I remember being at a park several years ago where one camper was complaining to the park about sewer smell at their sight. Cause.... dump valves open.

And a grey tank that is not occasionally cleaned can smell as bad or worse than a black tank. Occasionally before I dump I'll add some laundry detergent to the grey tanks, let it slosh around overnight then drain.

YES and NO. The stink will migrate back thru the BLACK tank via the toilet down tube to the black tank. IF, as the op found out, your GRAY tank system is not installed correctly, then ANY odor(valve open or not) will migrate back into the RV. BUT in a correctly installed GRAY system, the P traps STOP the backfeed of odor. Which is the purpose of P traps. THE MAIN REASON TO NEVER LEAVE VALVES OPEN IS BOTH THE DREADED POOP PYRAMID AND THE GRAY TANK SLIMY DEBRIS FROM GETTING IN THE VALVE CREVISES AND NOT ALLOWING A FULL CLOSURE AND THEN LEAKS. DOug
ktmrfs
Explorer II
Jul 18, 2022
dougrainer wrote:
ktmrfs wrote:
wa8yxm wrote:
Question: Many advise that when you are on a full hook up site to close your black tank (And they explain the reason I won't here) but leave the gray open till you are getting ready to leave.

NO. Close both valves and dump when you have to.

Why?
Ever see the ads for the RV Black Tank treatments that basically are a waste of money.. A Stinky RV that everyone is avoiding?

Well the Stink is not coming from the holding tanks ..it's coming from the park's sewer system up the 3" hose and into the GRAY tank via the open valve.> Close the valve to block the stink..

EXACTLY ON KEEPING VALVES CLOSED!!!! sewer lines doesn't have a P trap. I remember being at a park several years ago where one camper was complaining to the park about sewer smell at their sight. Cause.... dump valves open.

And a grey tank that is not occasionally cleaned can smell as bad or worse than a black tank. Occasionally before I dump I'll add some laundry detergent to the grey tanks, let it slosh around overnight then drain.

YES and NO. The stink will migrate back thru the BLACK tank via the toilet down tube to the black tank. IF, as the op found out, your GRAY tank system is not installed correctly, then ANY odor(valve open or not) will migrate back into the RV. BUT in a correctly installed GRAY system, the P traps STOP the backfeed of odor. Which is the purpose of P traps. THE MAIN REASON TO NEVER LEAVE VALVES OPEN IS BOTH THE DREADED POOP PYRAMID AND THE GRAY TANK SLIMY DEBRIS FROM GETTING IN THE VALVE CREVISES AND NOT ALLOWING A FULL CLOSURE AND THEN LEAKS. DOug

If the main dump valve(s) are open there is then NO P trap to keep sewer odor from going into the empty tanks, up the vent tubes and out the top of the trailer and then having an odor problem around the trailer like an open sewer pipe. Yes, the P trap in the sink etc. keeps the odor from coming directly through the sink etc. drain into the trailer.
Bobbo
Explorer II
Jul 21, 2022
You can always put your own P trap in the stinky slinky if leaving the gray valve open.

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