Gray Water Tank ?

Gray water stinks. Traps and vents should keep the smell from coming inside, just like waste plumbing at home. A blocked vent, or malfunctioning anti-siphon can cause tank smells to get inside. You can perfume the tank, but better to fix the venting problems.

definately check your anti siphon under sinks. Ours went out last trip and was horrible. Been trailering 40 years and WHAM. We bought 3 , one for each potential sink. Grand Design also told us it is more important to treat gray tanks, since they do not get rinsed.

Y'all have given me a lot to consider/investigate. I may put some bleach in the tank before the next trip and see what my camper smells like upon arrival.

I didn't know about those air admittance valves, thanks for the heads up on those Clay L.

I know there isn't much room under my shower I wonder if it has one of those traps that ependydad mentioned.

Thanks again for all of the replies!

From time to time, I just run water to be sure the traps are full and all is good.

Clay L wrote:
There are usually air admittance valves on the kitchen and bathroom sinks. It comes off a stub on the sewer side of the traps. It has a flap that opens when the gray water is dumped so water is not sucked out of the traps. If the flap does not close properly odor can escape the gray tank. That might be where the odor is coming from.
The air admittance valves usually can be unscrewed by hand. Replacements can be obtained many hardware stores

Thanks & interesting. My rear bathroom's sink goes directly to my second black tank. We get a terrible odor in there from time to time (literally always have from when the camper was very new). I have seen this valve, but didn't know how it worked.

I think I'll investigate that a bit further. :)

GWolfe wrote:
I tried searching with no luck.

Do y'all add anything to the gray water tank? I add stuff to the black water tank for odor control and to help break things down but never the gray water. Sometimes I will get a bad smell in the camper and wonder if it's coming from the gray water tank, usually after a long drive is when I notice it the most.

Yep. I've noticed this for quite a long time. I know my camper doesn't use a standard "p"-trap. It has some modified version that is supposed to hold water, but it's still straight.

This type, drives WILL let the water out of this trap. And you wish get a rank smell from your gray tank.

We just bought this stuff and it solves the smell.
http://www.amazon.com/gp/product/B005XEFADU

I also immediately run water in the sinks when we get to where we're going.

lanerd wrote:
If you have an odor, weather from the gray or black tank, you don't need to add chemicals, you need to fix the problem that's causing the odor. Adding chemicals is just masking the odor and is just wasting money.

Before starting your "investigation", dump some bleach down the drain.

There are usually air admittance valves on the kitchen and bathroom sinks. It comes off a stub on the sewer side of the traps. It has a flap that opens when the gray water is dumped so water is not sucked out of the traps. If the flap does not close properly odor can escape the gray tank. That might be where the odor is coming from.
The air admittance valves usually can be unscrewed by hand. Replacements can be obtained many hardware stores

GWolfe wrote:
I will do some investigating then. Is it possible for the water to slosh out of the traps? I ask because it is not very often it happens and usually when it does it is after a long drive.

Thanks for the replies.

Not real likely but definitely possible on some roads.

I will do some investigating then. Is it possible for the water to slosh out of the traps? I ask because it is not very often it happens and usually when it does it is after a long drive.

Thanks for the replies.