mystery odor source

[Coolbaldguy]

Not exactly a mystery....I know WHAT it is, just not exactly WHERE it is coming from. I have started to get a sewage odor in the bathroom. This weekend at a campground with full hookups I connected to the campground sewer and left the gray tank valve open. I normally leave the valves closed on weekend trips and just drain before we leave on the last day. This time we had our son, daughter-in-law and 2 grand babies with us, so I decided to leave the gray tank valve open. After a day and a half I closed the gray tank valve so it would start holding water to "flush" the black water through the stinky slinky. After closing the gray valve we started to get the smell. The hose and drain valves are all in good condition, no leaks, no malfunctions, I am not an odor connoisseur but it smelled like gray water NOT like.....well you know...poop . I recently had the toilet off and repaired the water valve and replaced the ball and seal so I know those are in good condition and we have had a few trips without noticing any smells since I completed those repairs. My thinking on this has led me to think that it might be a plumbing vent issue? Any advice would be appreciated.

[Flybob]

Check under the sink for an air admittance valve ( see photo) try tapping it. They have a history of sticking.

[bambamdrw]

I make a Trap in my Flexible Sewer Hose. Where the flexible sewer line comes out of the bottom of the camper down to ground. I put a hump in the line, usually a 6x6 block of wood to create a trap. Basically a section of the Flexible Sewer line full of water will help prevent the gases from coming through.

[LTZ470]

Do you have the water level set in the "john" to cover the flush opening fully?

[Coolbaldguy]

Flybob, I do have a "studor" vent. I just checked it and it seems to be good. That was an excellent suggestion....I didn't know I had one! It was up so high that unless I got down on my knees and looked up o wouldn't have seen it.

[Coolbaldguy]

Originally Posted by bambamdrw

I make a Trap in my Flexible Sewer Hose. Where the flexible sewer line comes out of the bottom of the camper down to ground. I put a hump in the line, usually a 6x6 block of wood to create a trap. Basically a section of the Flexible Sewer line full of water will help prevent the gases from coming through.

I have done that before as well....but this time the smell started when I closed the drain valve, so a trap in the hose wouldn't have made a difference.

[Coolbaldguy]

Originally Posted by LTZ470

Do you have the water level set in the "john" to cover the flush opening fully?

Yes, I just recently changed the drain valve and seal. A little water always sits on top keeping a wet seal.

[WolfWhistle]

I would clean those tanks with washing soda, borax and laundry detergent... flush well the sanitize when I got home. I've heard, twice a year. A grey tank should not be that smelly. Full P-traps keep what might be there at bay. I suppose you could have a breeze somehow blow air into the camper.

[halla]

Weird but did your roof vent get clogged recently? Bees or something else that would cause the backup?

[Flybob]

A great thing for cleaning and sanitizing waste tanks is Odoban ( big box stores). Kills most bacteria and viruses.

[SeaDog]

Gray tanks can really stink, sometimes it the p-traps in the sink and shower that have gone dry sometimes it's the direction of the wind on your vent cover. I used to get stink in my class A until I installed the cyclone vents. It is a good idea to clean the scum in the gray tanks. Be careful what you use to clean if your next dump is at a campground with sceptic system.

[Flybob]

One other idea. Do you have an unused laundry hookup?

[Coolbaldguy]

Thanks everyone for responding. The odor has mysteriously left the premises. Here is my theory as to what happened. And it sort of goes along with Flybobs suggestion. When I dumped the black tank, the vent thing under the sink stuck CLOSED. That would cause the trap at the lavatory sink trap to be sucked dry (the bathroom sink is connected to the black tank). I then got an odor until someone would have used the sink and refilling the trap. I will be on 10 day trip soon and will have plenty of time to explore this theory. I will keep you all posted.

[DAISY BOYKIN]

Odor in the bath can be terrible. I discovered bad odor can be caused by putting my RV in storage and not plugging the drains. I now close the lavatory
drain and shower drain in the bath. I also put the sink drains in the kitchen.
Once the water in the "P" traps evaporate, tank gas can get into the RV through the drains. So that little Plastic drain plug that you do not use in the shower should now be closed along with all the other drains when placing your RV in storage.

[kaulick]

We had both our black and gray tanks bow in the middle and detach from their connection which has caused sewage leakage in our compartments and sewerage smell coming up through our air vents since the compartment is vented for heat. This is an issue that was worked on by our dealer but their fix didn’t work and we are heading up to the factory to have the issue fixed.

Look and see if you tanks bow in the middle. Is the sewage smell in your compartment? See if sewage is leaking between the small space in the middle of the compartments.

[TitanMike]

Gray water tanks can stink sometimes more than the black tank. People need to pay almost as much attention to keeping the gray tank clean as they do with the black.

Soaps from the shower and sinks, along with any food scraps from dish washing, can ferment into a nasty, stinky mess.

I just add a citrus smelling gray water tank "Tablet" in the bathroom sink drain and dissolve it with running water as I finish up my tank draining process. Does a great job and I just buy something cheap.

[Scrapper]

Do you have an actual p-trap under the shower or tub? Manufacturers sometimes use a HepvO waste valve instead of a trap. They can cause odor backup if something gets in the flap and keeps it open. Long hair can cause it to not function properly.