My laundry has a washing machine, a large sink, a toilet and a small hand basin. The washing machine drains into the large sink.
We sometimes notice a sewer-like smell in the laundry. I'm trying to figure out what might be causing it.
I read this post, which seems to fit. The noise isn't troublesome, but the occasional sewer smell is.
The hand basin gets very little use. I wondered if its P-trap could be drying up and letting sewer gas into the laundry, so on a smelly day I ran water into the hand basin and ventillated the room thoroughly. The smell came back.
The large sink drains quickly, but gurgles once all the water has gone down. I wonder if this is the sound of the water being dragged out of its P-trap by the long sewer pipe that leads from our house down to the street sewer about 10m below. Water goes down through the plug hole, around the P-trap, then horizontally into a stud wall, then to who-knows-where.
| sink | \____ ___/ |v| __ | |___ / _| |_ \ |v| | | |^| | | | | | | P-trap | | | |v|_|^| | wall | | \__>_ / | |v|______________________ \____>______________>____ |