Sewer gas?

[Mattias1]

We are connected to the campground sewer. We have 2 black tanks (closed) and 2 grey tanks (open). This morning we got up to the smell of strong sewer gas inside the unit? Checked all of our sinks and toilets and couldnt find a culprit - why does this happen?

 

[SC5thWheeler]

Is the smell inside or outside?

Possible smell sources:

- someone flushed the toilet with the bathroom fan running. The fan sucked swamp gas out of the toilet

- The water in the p-trap of a sink has evaporated and the smelly air gets out, just needs a splash of water

 

[Gary RV_Wizard]

You almost surely have "air admittance valves" (AAV) under each sink and the flapper in it sometimes fails, allowing gases from the gray tank to enter. It's an easy replacement and the AAVs are readily available wherever plumbing supplies are sold.

Overheated & over-charged batteries will outgas and the gas smells much the same as sewer aroma (it's hydrogen sulfide or "rotten eggs").

 

[Mattias1]

Thanks! FYI - the smell is inside. Could propane smell like that?

 

[SC5thWheeler]

Thanks! FYI - the smell is inside. Could propane smell like that?

Well propane has its own distinct smell. I would not describe it as a sewer smell.

 

[Onyrlef]

First, the gray tanks shouldn't be open.

 

[Larry N.]

First, the gray tanks shouldn't be open.

We usually left the gray tanks open and never had a problem -- black tanks is another story, though. Likely Gary and fifthwheeler's comments are more pertinent...

 

[Domo]

We leave the gray tanks closed unless we are doing laundry or some other heavy gray water usage (such as the annual showers). With them closed up, we can dump the black and then use the contained gray water to help flush the lines clean until next time.

 

[Bobtop46]

Force a P Trap in the sewer hose going to the campground. This will also stop smells and sewer gnats from getting inti your unit.

Other possibility is that you dumped black tanks recently and didn't put enough water back into the tank to charge it, or cover the bottom of the tank.

 

[darsben]

We leave the gray tanks closed unless we are doing laundry or some other heavy gray water usage (such as the annual showers). With them closed up, we can dump the black and then use the contained gray water to help flush the lines clean until next time.

ANNUAL SHOWERS please explain

 

[Kirk]

Could propane smell like that?

Propane has an odor that is much like rotten eggs and it is also heavier than air (the reason your propane alarm is near the floor) so it would trigger an alarm.

Sewer gas is always present in the piping of any sewer system and there are several things that should prevent it getting into the RV, even when the gray dump valves are left open. As Gary suggested, a failing air admittance valve can cause that and you should have one under each of your sinks. They will look similar to this:

Another thing that can cause the odor is for the P traps under the sink to have lost the water that is normally in them. That can sometimes happen when connected to city sewer for an extended period. When parked for an extended period I always do as suggested in post #9 and create a P trap in the sewer hose which is very effective for prevention of gasses from the sewer system.

 

[Domo]

ANNUAL SHOWERS please explain

Well, sometimes we're delayed by a month or so.

It's amazing how much room we seems to get in campgrounds! Always seem to have an empty site on both sides of ours by the time we get to the seventh month!

Somehow I think they are related facts...

 

[Mr Lars]

Well, sometimes we're delayed by a month or so.

It's amazing how much room we seems to get in campgrounds! Always seem to have an empty site on both sides of ours by the time we get to the seventh month!

Somehow I think they are related facts...

I could say something here, but will refrain.

 

[darsben]

Sorry I asked

 

[Domo]

Sorry I asked

You should know me by now!

 

[John From Detroit]

EVERY time and I mean EVERY time I had that problem I'd left the Gray valve open.

Unless you form a Water trap with the sewer hose sewer odor from under ground backs up and out. That said looks like you were properly trapped.