Sewer Smell Issues

[smcdonald83]

This past June we purchased a used 2018 Coachman Viking. We have not been able to take it anywhere yet but sometime in July (after it had been very hot) we opened it up and there was an awful smell coming from all of the drains (toilet and sinks). Not really a sewage small but a sweet (although very offensive) kind of smell. I checked all of the valves and they were closed like they should be. I hooked it up to water and flushed a significant amount of water through both tanks and all fixtures. I also flushed the vent pipes and have a sprayer nozzle that I put down the toilet. After flushing the system I ran a bunch of water and put some septic treatment down the toilet (which we have not used). The smell is better and I do not notice it so much on the inside anymore but if you walk by it and the wind is blowing just right you get a whiff of that smell again. I am not sure what to do. I have never smelled anything like this from a camper and it is not really a sewage smell. Any thoughts on what could be causing it? What I can do to fix the problem? I am worried they may have winterized it last year with the incorrect antifreeze. Thoughts?

 

[Scotttkd2]

It is also possible the traps dried out and you were getting a whiff of the grey tank....it can smell worse than the black tank. My wife complained of smelling sewer intermittently in our class A, and I had lost a vent cap due to a tree limb, and had replaced with a generic one. Found anti siphon 1 way versions, installed those and she has not noticed smell since.

https://www.amazon.com/dp/B01CZQ9Y6M/?tag=rvf01-20

 

[John&Andrea]

Check your house battery. Years back on a TT we owned our battery was bad and we were sure we had a tank issue. Weird but true.

 

[Rosy]

If it's sweet, could there be anti freeze sitting somewhere? When I was blowing out my lines for winter, I realized that when I was flushing out the antifreeze that the previous owners put in last winter, I forgot to do the outside shower.

 

[IowaRVer]

Could it be you have a Dometic 300 model toilet?

While no longer manufactured by Dometic… my 2022 trailer built in Dec. 2021 has one (I’ve called Dometic and they are sending a replacement model to my dealer)

not all of the 300’s will have a problem, but under certaIn circumstances… many will collect waste in the bottom of the unit near floor level and it doesn’t drain… it just ferments there

if you have a model 300… it’s worth doing a search to read about it... and then make up your own mind about what to do about it

Dometic is quite aware of the issue and cooperative if you call them

 

[IowaRVer]

Could it be you have a Dometic 300 model toilet?

While no longer manufactured by Dometic… my 2022 trailer built in Dec. 2021 has one (I’ve called Dometic and they are sending a replacement model to my dealer)

not all of the 300’s will have a problem, but under certaIn circumstances… many will collect waste in the bottom of the unit near floor level and it doesn’t drain… it just ferments there

if you have a model 300… it’s worth doing a search to read about it... and then make up your own mind about what to do about it

Dometic is quite aware of the issue and cooperative if you call them

Sorry… I misread your post. You said smell is coming from your gray tank via the sinks… so disregard my post about the toilet.