LPT for all floor drains, really. Did work in a hospital recently, in their 6th floor testing lab. A few rarely-used rooms with equipment I needed to certify smelled like bathrooms. Took close whiffs of the drains, poured half a Nalgene of tap water down them, and boom. Left a note for the occupants, got an email a few days later from our point of contact with thanks on behalf of the lab staff.
It's silly; highly-trained professionals (talkin' PhD types) just avoided rooms with necessary equipment rather than even make a complaint to their facilities manager. Well, now he knows, and added 3 rooms to his weekly preventative maintenance walkthrough list of rooms with drains needing water. Heh.
Edit: From a Direct Message: "Pour some water, then some mineral oil. Water will occupy the space of the trap, then the mineral oil will sit on top and prevent evaporation of the water. Useful in areas where the drain is not having things washed into it often."
Edit 2: Took a snarky dig at highly-trained professionals. Meant in light jest, but in reality my work is contingent on those people needing the equipment I work on. Also the street has worked both ways, and I've been corrected on something that is silly to me now, too. Life is fun.
Wow, this has been happening ever since I moved into my house two years ago. I only get the smell when I'm running the washing machine. Any ideas why that is?
I lived in an apartment with no closets but with an unnecessary spare toilet and sink in a closet sized room. I stacked the room floor to ceiling with boxes of books and stuff, so clever. Learned about the existence of traps the hard way a few weeks later.
Add a table spoon of vegetable oil on top, helps prevent the water drying out of the trap.
Can you explain what that does and why it helps?
Wouldn’t that turn my house into a trap house?
Will add one thing I learned about the 'master trap' if your house has one...
My basement has 2 drains added in a renovation and if the sewer line gets blocked up, water can back-fill out from these traps, even if the main line is onl;y partially blocked.
Turns out that you don't always need a 'snake' or a professional plumber to clean out the sewer line if you have girls with long hair at home. That big hairball that inevitably clogs up the master trap (just before your sewage line goes to the street) can be cleaned very easily with a WetVac - This thing is a truly Amazing device for not only vacuuming up water from the initial spill (don't bother with a mop and bucket) of a backed up drain, but also for cleaning out the main line's huge hairball.