ernie1 wrote:

Make doubly sure the traps under your sinks have enough water in them to form a seal that will not allow sewer gases back into the coach. I had that problem in the past where after traveling for a bit of time or after having just dumped the gray tank waste which might siphon out the trap, I would get a foul odor from the gray water tank. Nowadays, I try to remember to screw down tightly the sink drain plug which prevents the loss of liquid in the trap.

bukhrn wrote:

You mentioned that you get the smell with the AC running, do you get the same smell from the sink area Without
the AC on?

ernie1 wrote:

Make doubly sure the traps under your sinks have enough water in them to form a seal that will not allow sewer gases back into the coach. I had that problem in the past where after traveling for a bit of time or after having just dumped the gray tank waste which might siphon out the trap, I would get a foul odor from the gray water tank. Nowadays, I try to remember to screw down tightly the sink drain plug which prevents the loss of liquid in the trap.

Dave in TN wrote:

This product worked for me when we encountered grey tank odor issues. Of course if your problem isn't tank related this wouldn't help.

https://www.amazon.com/Camco-40597-Black-Cyclone-Plumbing/dp/B00SQ1K19A?th=1

Wulrich wrote:


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.

opnspaces wrote:



Has the gray tank ever been removed? It sounds like there is a break or separation high up in the vent pipe. What I would do. First drain the gray tank so there is lots of air in the tank. Climb up on the roof with a bottle of Pine Sol and a roll of duct tape. Take the cover off the vent pipe and make sure it sticks up out of the roof and the pipe is sealed all the way around the exterior. If it is not sealed or doesn't stick up you have a potential problem.

Carefully pour about a cup of pine sol down the vent pipe but do not splash it outside the pipe. Now slap a piece of duct tape over the end of the pipe to seal it off.

Go down and start the AC and then run the kitchen sink. Does the smell come out? If it still smells shut everything off and remove the air admittance valve and slap a piece of tape over the end of the pipe. Repeat the test again. Does it still smell?

Alternatively. Leave the tank with a bunch of water in it. Go to a place that sells dry ice (in my area a few grocery stores and Baskin Robins ice cream stores sell it) Buy about 2 pounds, leave the dry ice wrapped up and take it up on the roof in a dry bucket and a hammer. Break up the ice into smaller chunks with the hammer and drop it all down the vent pipe. Give it a minute or two to really start melting and then go turn on the AC and sink. Hopefully you can see the vapor from the ice escaping where the stink is coming out.

Do you have or know anybody who has a Halloween smoke machine? Maybe you can rig it up with a 10 foot hose and run the hose down the vent pipe and into the gray tank. Now fill the tank with fog. Wait a few minutes and test for leaks.

JimK-NY wrote:

Do I understand there are no odors unless the A/C is running? If that is the case, I don't see any connection with the grey water. I would check the A/C. Maybe a dead critter in the unit. As mentioned the A/C does not pull any outside air so the offending item would be inside in the A/C or ductwork if there is any.