2021 3120RL Vanity sink smell

[jeepman71]

I have a 2021 3120RL. For a while now we occasionally get a bad smell when washing our hands in the sink. I don’t believe it is coming from the tank because it happens Evan after the P trap would be full. I looked for a Studer vent but the drain plumbs into the wall. Any help would be greatly appreciated.

[Carl n Susan]

One common cause is being prepped for a washer/dryer but not having one. The water to the washer spigots get very funky after a while. Attach a short hose to the cold and hot water spigots (one at a time) and flush the lines out (use the washer drain line for the output).

[RMcNeal]

What Carl said. I ended up putting cut off valves in the basement that have a drain feature so there's no water in the line going up into the bedroom closet. I put the valves right after the Tee where the lines feed the washer plumbing so that section of pipe has no water in it until we get a washer at least.
https://www.homedepot.com/p/Apollo-1...12WD/305469319

[jeepman71]

Thanks for the reply, that thought never crossed my mind. I’ll give it a try and let you all know how it turns out.

[scattershot]

That was the problem with our 2955. Shutoff valves in both washer lines fixed it

[daglenn1960]

We had a different issue with our 21 3121rl/legacy, the toilet flange was not properly sealed/seated. A bathroom smell would increase as the black tank filled. Thorough investigation of basement/plumbing showed a slow leak around the toilet flange to black tank downpipe (ours was a threaded flange), with poor placement of sealant in the joint.

I removed/replaced the flange with better quality sealant properly applied, and we have not seen a leak since or had the smell.

[Daryles]

I also put shut off valves to the washer behind the basement walls.

[jeepman71]

We flushed the lines and so far no smell. Thanks!