Sewage odor is not right

[Tmayer]

I just purchased my second travel trailer the first one never had a sewage smell at all coming from the toilet and our newer model year 2013 has only been camped in one time by us and smell of sewage is horrible. I have emptied the black water tank. Added RV deodorizer/waste breakup then drained that. Flushed through with fresh water and then drained that. The smell remains. What am I missing and how do I correct the smell? It did not smell when the previous owner showed it to me.

[BrianGlenn]

If there are any P-traps that have dried out (washer plumbing but no washer, etc) you may have gases passing back into the trailer even after one use of the black/grey tanks. Another possibility in a used trailer is the anti siphon vents under a non roof vented sink P-trap may be faulty. They look like this.


Brian

[Spdracr39]

We had a bad smell that I thought was the black tank but it turned out to be they grey. We do not use the shower and I figured out the p trap had dried out in there. Ran a little water in it and it is all good now.

[TDI-Minnie]

Make sure the roof vent is not clogged.
Get on the roof with a hose and blast down into the tank.

[Ranster]

Are you sure it is sewage smell? Where did you camp and could a rodent have gotten into a storage area, etc. and died?

[ga traveler]

Add some waste treatment to the grey water tank. If the smell still does not go away, check the pilot lights. Some of my customers mistook the smell of lp gas for sewage.