Practically overnight, my laundry room smelled so badly I thought something had died. Have pulled out washer and dryer, nothing there.

Ran several cycles (9 in fact, and 2 with bleach only) of front-loading washing machine cleaner through the machine and although it is much improved, the smell is still there and wafts upstairs through the HVAC vents.

I cannot smell anything in the drain hose itself, or the drain of the laundry sink beside the washer. There's no floor drain and the smell is not coming from the HW heater in the same room.

I've drained the washer's overflow and it was clean as a whistle, only smelled like the cleaner's chemical smell I've been using. The rubber/plastic door piece on the washer does not smell, I've wiped it down a couple of times and gotten inside the folds. In fact, when you stick your head in the washer, can't smell a thing. However, there is a verrrry slight smell that seems to stick to laundry once it's been washed.

Do I have some kind of venting problem perhaps?

So what are you actually smelling, damp? Grey water? Dead rat? The fact that things are better after cleaning the washing machine suggests it was at least part of the problem and maybe there is damp in a corner or under a cabinet. I know my old washing machine smelled like at sewer at times before it was replaced, so drain cleaner down all the drain pipes, open the drain in the utrap under the sink to make sure it is clean, air the room and use a spray disinfectant and maybe your room does need a vent if the window isn't opened often Try running a cycle through the washing machine with white vinegar. Check behind and under the water heater to make sure it hasn't developed a leak and is conributing. You obviously have a room with heat in it and that can help bacteria grow. Smells can migrate up drain pipes if the water in the Utrap isn't at the right level, that can happen if there is a blockage

The smell is a combination of mustiness and horrible sewer. I had the dryer vent blown out (just in case it was a rodent in there) and the service guy said it was definitely a water/sewer-ish smell, not a "dead" smell.


I'll be sure to try a drain cleaner on the laundry sink and the washing machine drain. Thanks for that suggestion!


I've checked for water leaks, nothing at all visible.

Mustiness suggests moisture which suggests leaks and mould growing somewhere even under the floor. Sewer suggests faeces which can lodge in washing machines if they are used to wash soiled clothing, it also suggests blocked drains and cracked waste pipes or seals on the pipes. Check that the waste pipes are solid and stable and the seal isn't cracked put the two together and you might have a cracked pipe under the floor. is your house standalone or part of a complex?

Your service guy didn't suggest a solution or a plumber?

Mustiness suggests moisture which suggests leaks and mould growing somewhere even under the floor. Sewer suggests faeces which can lodge in washing machines if they are used to wash soiled clothing, it also suggests blocked drains and cracked waste pipes or seals on the pipes. Check that the waste pipes are solid and stable and the seal isn't cracked put the two together and you might have a cracked pipe under the floor. is your house standalone or part of a complex?

Your service guy didn't suggest a solution or a plumber?


It's a single family dwelling, and no, he was there just to blow out the dryer vent. :)

The smell happened literally overnight, one day it was fine and the next day it was like walking into a wall of stench! I think if it was something that had been leaking for a long while, I would have caught whiffs of it long before.

I've ruled out everything I can and aside from climbing up on the roof to check the vent stack (which I don't feel comfortable doing), I think it's time to call in a plumber/drain specialist so they can have a look.

I'll be sure to leave a note here regarding what the experts come up with!

Thanks for your help.

This sounds like sewer gas getting inside posibly from a dry trap which could be caused by a clogged vent.

The pros checked the roof vent stack, it seemed clear so they snaked the washing machine and laundry sink drains. They seem to think something (trapped fabric/hair etc) may have been wicking the moisture out of the P trap. The smell seems to be gone, crossing my fingers it stays that way!