Honestly, I wouldn’t count on those blue enzyme things for this kind of smell—they’re more for breaking down gunk, not keeping sewer gas out. Trap primers are a whole different animal. They actually keep water in the trap automatically, so you don’t have to play “remember the drain” every week. If your basement’s ancient and the smell shows up after rain, you might want to check if your floor drain trap is cracked or dried out, too. Sometimes it’s not just about humidity swings... old pipes can be sneaky.
Sometimes it’s not just about humidity swings... old pipes can be sneaky.
That’s the truth. I’ve seen a cracked cast iron trap that looked fine from above, but the bottom was rotted out—took ages to find. Ever notice if the smell gets worse when you run laundry or flush upstairs? Sometimes negative pressure pulls sewer gas right through those hidden cracks.