Black water smell

[Gentracker]

I have a 2012 Winnebago Vista, 35f, with a mid coach bath on passengers side. It has a macerater pump that pumps waste thru a hose to wet bay on driver’s side, rear.

I bought it used 2 years ago with only 11,000 miles. It has always had a slight odor coming from under sink area but recently while working in electrical bay (driver side just behind rear wheels) I noticed it there as well.

Now I had macerator pump replaced this year and the dealer thought this may have been the issue.

Still has smell.

I’m thinking since waste pump hose runs through electrical bay that maybe the hose is source.

Has anyone experienced same issue or have input.

Stinky in IL aka bruce

[ThomB]

This sounds like the AAV under the sink. (Air Admittance Valve). Because it's more difficult to vent the trap through the roof they use the aav to draw the air into the system to release the suction you'd get without a vent. The factory aav isn't the best one that you can buy. Go to one of the big box stores and you will likely see 3 versions of this in the plumbing section. The cheapest will likely match the one installed. Buy one of the better ones and install that. When we did it we changed them out on all the sinks.


I used this one: https://www.homedepot.com/p/STUDOR-1...0341/202275238
Others have had good luck with this: https://www.homedepot.com/p/Oatey-Su...9230/205395535
The one you will be replacing will most likely look like this: https://www.homedepot.com/p/Oatey-1-...9012/100204205

[Gentracker]

Originally Posted by ThomB

This sounds like the AAV under the sink. (Air Admittance Valve). Because it's more difficult to vent the trap through the roof they use the aav to draw the air into the system to release the suction you'd get without a vent. The factory aav isn't the best one that you can buy. Go to one of the big box stores and you will likely see 3 versions of this in the plumbing section. The cheapest will likely match the one installed. Buy one of the better ones and install that. When we did it we changed them out on all the sinks.


I used this one: https://www.homedepot.com/p/STUDOR-1...0341/202275238
Others have had good luck with this: https://www.homedepot.com/p/Oatey-Su...9230/205395535
The one you will be replacing will most likely look like this: https://www.homedepot.com/p/Oatey-1-...9012/100204205

First thanks for the reply.

But Do you think that would explain the smell in the electrical bay which is on opposite side of coach?

[ThomB]

Not sure I can answer that part. My understanding is that the macerator in the 1/2 bath feeds over to the black tank then it's dumped from there. Yes, there could be an issue with the hose, but I think you'd have other tell-tale signs (fluids) that you would see if that were the case.

[Gentracker]

I agree. I have to look at plumbing to check for the vent device tomorrow. Thanks again

[indieaz]

Curious if you ever figured this out?

I have the same issue in my 35F with a black tank odor smell in my basement (wet bay/electrical and the macerator compartment on the passenger side).

This smell also seeps up from the basement to any place where plumbing penetrates into the basement (behind fridge, electric fireplace, W/D unit). I have combatted the smell with religious use of tank deoderizers and half full tanks of fresh water while driving. It seems like the macerator 1" hose is allowing sewer gas to escape while no liquid waste is leaking. I alos wonder if the vents from the black tank are suspect, but I don't see how you can possible access the top of the tanks.