How Are Vent Stacks Attached to the Waste Tanks

[KJRitchie]

How are the vent stacks for the black and gray water tanks attached? Wondering why you would smell sewer odor in the trailer when all the windows and vents are closed.

Kelvin

[AlinCal]

If the trailer is not being used it is possible to have a dry trap, although those fixtures would be grey water. On our trailer the toilet sits over the blk tank and a seperate vent comes off the tank and out the roof, independant of the grey system, do you keep water in the toilet? Does it hold water?

[perryg114]

Gray water will sour over time and have a strong sulfur odor. Dry traps will let it in the trailer. Kitchen, bathroom sink, and shower traps need to be full. A dry toilet seal or bad base gasket can let odor in as well. The ABS/PVC vents go through the roof sheet metal and there is a rubber gasket that crack shorty after installation and a metal square TeePee and screws that seal the rubber to the roof. The Teepee does not have a top on it so water can pour right in. I ended up putting caulk around the pipe and sealing it to the roof. Not a permanent fix but has worked for 5 yrs. Best to use some deodorant in the black tank if you don't want the smell finding its way into the trailer. It probably only takes a few part per million of sewer gas before you smell it. Hard to seal 100% on anything as crude as sewer systems. Summer heat and a full black water tank and no tank deodorant will make for a smelly trailer. Gray water stinks worse than you think it does so don't rule dry traps out.

Perry

[KJRitchie]

Currently both tanks are empty, just got back from a weekend trip where I dumped both tanks and primed the black tank with about 3g of water and TanktechRX. Bathroom smells OK. I can smell some sewer odor coming from the hallway closet water pump access hatch next to the shower. Shower smells OK I have my two roof vent fans on, front sucks air in and rear vent fan blows air out to keep the trailer aired during open storage. Weather has been in the mid 80s and humid, some rain.

Just surprised when I went out to the trailer yesterday afterwork and smelled sewer odor.

Kelvin

[bel73]

You might be pulling air through one of your auto vent valves. Had to remove and clean one that would not seat properly in our 23D.

[gdanderson]

Cooking batteries smell amazingly like sewer gas????

Greg Anderson
Wisconsin

[johnmcclorey]

When running the roof vent on exhaust, I have pulled black tank air through my toilet into the coach when the toilet needed new seals where it seats on the black tank.

[InterBlog]

OP, your tile lists a 2008 trailer; my husband and I own a 2007 MH, very close in age to yours. If Airstream plumbed each in a similar way, you may have a cracked vent line which has allowed some black water to seep out, leading to odor.

My husband and I suffered from the infamous plumbing defects of that era, which caused our gray tank to shear away entirely from its three lines, and the common vent line to shear off the black tank. You can read about our vent line DIY repair job here, and our gray water fix in Part 1, Part 2, and Part 3 of a blog post series I wrote.

Note that a vent line crack, if present, may be subtle and may not fully activate until your rig is on the road and vibrating around. We helped some friends to re-plumb their rig this past weekend (they have the same model and year that we do), and I had to look carefully to confirm that their vent line was, in fact, partially sheared, just as ours had been.

I don't know if this build issue extended to any trailers, or was restricted to just Airstream's Class B vans. I'm curious to find out.

[perryg114]

If you are sucking in air from a roof vent there is your problem. Put all your vents on exhaust and open a window. Your most likely pulling in fumes from the vent stacks into the trailer.

Perry

[dennis ross]

Can you use the same vent stack for grey and black water tanks?

[AlinCal]

Yes