I’d echo the sump pump idea—had one seize up after a power outage, and the smell was unreal before I even noticed water. One thing I’d add: check any stored cardboard boxes. They soak up moisture and can get musty fast, especially if they’re tucked behind furniture. Also, don’t overlook HVAC ducts if you’ve got them running through the basement. Sometimes condensation in there can be the culprit, and it’s easy to miss.
Funny you mention the cardboard boxes—I've had tenants swear up and down they didn't have any water issues, only to find a stack of old moving boxes hiding behind a couch, basically acting like sponges. I always wonder how many folks forget about stuff stored under stairs or in those weird basement nooks. Ever try using plastic bins instead? Saved me a few headaches, though nothing's totally foolproof.
About the HVAC ducts, I've seen condensation drip right onto the floor joists and run down behind finished walls. Took me forever to figure out why one corner always smelled off. Ended up wrapping the ductwork with insulation and that helped a ton.
Do you ever get that musty smell after heavy rain even if there’s no standing water? Sometimes I think it’s just the humidity, but then I start second-guessing everything—cracks in the foundation, leaky pipes, you name it.
Plastic bins are a game changer, honestly. Cardboard just doesn’t stand a chance once the humidity creeps in. I’ve chased that musty smell too, and it’s wild how sometimes it’s just air movement—or lack of it—rather than an actual leak. Dehumidifier helps, but I still find myself sniffing around after every storm, just in case.
I hear you on the plastic bins—cardboard just turns into a science experiment down there. I’ve noticed sometimes it’s not even about leaks, but just how air gets trapped in certain corners. Ever tried running a fan in addition to the dehumidifier? I’m curious if that actually helps move things along or if it just stirs up more dust.
I get the idea behind using a fan, but honestly, it can be a double-edged sword. Sure, it moves air, but if you’ve got any mold spores or dust settled in corners, a fan just kicks that stuff up and spreads it around. In my experience, focusing on sealing up any obvious moisture sources and letting the dehumidifier do its thing works better. If you really want to use a fan, make sure you’re cleaning first—otherwise you might just be making the musty smell worse.