Black tank smell in trailer

[gorpie]

I have a 2017 28.5 rlts that I bought new in Oct. 2016. I have never had a sewer smell inside it until the last time I used it, (about a week ago). I always start with water and sanitizer in the black tank before I use the toilet. I always use lots of water when I flush, more water is always better. When the tank gets ¾ to full I always dump the tank and run the black water flush. Then I shut the knife value and put water back into the black tank, then dump the tank again. I do this a couple time until it looks clear. I never lack on the cleaning of the black tank, it’s a pet peeve of mine. I hate smell.
So this last trip, about day four after I dumped my black tank I swear that I started to smell a little sewer inside the trailer, thought it maybe was my neighbor camping next to me. I got home and a few days later I went into the trailer tonight and I could smell it. Just a note that the inside of the trailer was in its ninety’s. Which it has been before with no smell. The toilet holds water. What else could I check?
Thanks for your help!

[2edgesword]

The one time we had this issue it was a clogged black tank vent. Somewhere along the line the vent tube shifted and it was right up against the cover not allowing the black tank to vent. Every time you flushed the built up gas came into the trailer. I removed the cover and cut a 1/4" section off the top of the tube and that cured the issue. Check the gap between the cover and the tube. If there is space remove the cover and look down the tube to see if there is anything obstructing it.

[Cavie]

Could be a bad AAV under the sink. ( air admittense valve ). They are cheep and fail often. some do not have one. some do, Lowes, HD, Hard ware.

[Rustic Eagle]

Some other possibilities could be a compromised toilet 'closet flange seal'...., and depending on toilet model the plastic two-piece bowl assembly joint could be compromised (happened on my retired Eagle).

As mentioned, those AAV's are notorious for grey tank odor.

Bob

[gorpie]

Originally Posted by 2edgesword

The one time we had this issue it was a clogged black tank vent. Somewhere along the line the vent tube shifted and it was right up against the cover not allowing the black tank to vent. Every time you flushed the built up gas came into the trailer. I removed the cover and cut a 1/4" section off the top of the tube and that cured the issue. Check the gap between the cover and the tube. If there is space remove the cover and look down the tube to see if there is anything obstructing it.

I checked the roof top vents and verified that they are all venting. Thanks for the suggestion.

[gorpie]

Originally Posted by Cavie

Could be a bad AAV under the sink. ( air admittense valve ). They are cheep and fail often. some do not have one. some do, Lowes, HD, Hard ware.

Attachment 60510

I checked both grey tank AAV and they both seem to be operating correctly. I think I still will get new ones.
I don't believe that the black tank has one? Thanks for thew suggestion.

[steveb285rks]

The lav sink in my ‘04 28.5 used to drain into the black tank and it had an AAV under the sink. Always had a weird odor. I replaced it with a plug, the sink drained fine and the smell was less.
Then the black tank cracked and when I replaced it I also re-plumbed the Sink drain to the forward grey tank. Fernco fittings are great! New AAV from Home Depot (just because) and no smell. Its been quite a few years now.

[oldmanAZ]

We're dealing with black and gray tank odors for the first time since owning the trailer. They seem to enter the trailer through the air conditioner.

Our 'fix' is to shut off the air conditioner whenever significant water goes into either tank... draining the sink after dishes, when showering, or flushing the black tank. It's working for us and the DW is ok with it. Might give that a try. Certainly easy to do.

[gorpie]

Spent the weekend rinsing and rinsing all three tanks, and then put deodorizer in all of them. It may becoming through the AAV like you guys said. They all seemed to check out but I will be replacing them. It seems much better in the trailer now. I will be going on a six day trip for the 4th July weekend, and so i will see or smell
Thank you everyone for your help.

[Marine71-76]

This is probably a stretch but are you sure it is from your black tank? Why? Because some times we get the smell and it actually is from our water - sulfur in the water lines. So when we flushed the toilet or washed our hands, we smelled it. This started last year with us & didn't always occur. So it took some paying real close attention to when it occurred.

This year wife started adding a good 2-3 squirts of blue Dawn in the black holding tank as well as the Pure Power Blue. Seems to be working so far.

[gorpie]

Originally Posted by Marine71-76

This is probably a stretch but are you sure it is from your black tank? Why? Because some times we get the smell and it actually is from our water - sulfur in the water lines. So when we flushed the toilet or washed our hands, we smelled it. This started last year with us & didn't always occur. So it took some paying real close attention to when it occurred.

This year wife started adding a good 2-3 squirts of blue Dawn in the black holding tank as well as the Pure Power Blue. Seems to be working so far.

I know it's not the water. I know that smell as I had it a year ago in my well water. Thank you.