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puchinno12's avatar
puchinno12
Explorer
Jan 12, 2016

Backflush sewer smell

Hello all; Whenever I dump the black tank and do a backflush, the sewer smell inside the trailer is pretty ferocious. There are no leaks of any kind in the bathroom. The fan is not on. No smell just draining the black tank but as soon as I hook up the hose and do back flush it stinks to high heaven. Anyone have any ideas? Thanks.

9 Replies

  • puchinno12 wrote:
    Thanks for the responses. The bowl has water in it when I back flush. The air admittance valve may have something to do with it, but seeing as how I am in Mexico for another couple months, I 'll have to wait till I get back to the States for a replacement. I thought maybe the vent line was plugged, but nadda. I have been using the fan to remove the smell" AFTER " backflushing and I will keep on doing so. It's not a major catastrophe by any means but it is a nuisance. Thanks again for taking the time to respond.


    Does your bathroom sink drain go to black tank?

    If so pace a baggie over the air admittance valve when backflushing.

    If it doesn't ..........then smell is NOT coming back thru the AAV
  • Put about 10 gallons of water in the tank and go for a nice drive with the camper. Before you do, put a cup of Tide or a few good squirts of Dawn dishing liquid in there too (or both if you want to be real adventurous!) Yea, it will bubble up, but it will go away too, leaving your tank smell much better when you flush it the next time.

    Another help is to put about 10 gallons of water in a couple cups of bleach. Go drive around, but drain the tank and flush it out immediately so the bleach will not deteriorate your slide valves. But this, definitely cleans up the smell.
  • Thanks for the responses. The bowl has water in it when I back flush. The air admittance valve may have something to do with it, but seeing as how I am in Mexico for another couple months, I 'll have to wait till I get back to the States for a replacement. I thought maybe the vent line was plugged, but nadda. I have been using the fan to remove the smell" AFTER " backflushing and I will keep on doing so. It's not a major catastrophe by any means but it is a nuisance. Thanks again for taking the time to respond.
  • 2oldman wrote:
    I don't try to stop it.. but I run the fan afterwards.. or drive.


    Also good advice, LOL.
  • I don't try to stop it.. but I run the fan afterwards.. or drive.
  • coolmom42 wrote:
    Make sure there is water in the toilet bowl covering the seal.

    Also replace the air admittance valve under the sink. They have one-way valves that quite often go bad and change into 2-way valves, letting the sewre stink in.


    YES..

    As for the air admittance valve under bathroom sink........that would only let stink from black tank back inside RV IF....IF bathroom sink drains into black tank
    Possible..just depends of how mfg. ran plumbing
  • Make sure there is water in the toilet bowl covering the seal.

    Also replace the air admittance valve under the sink. They have one-way valves that quite often go bad and change into 2-way valves, letting the sewre stink in.

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