Any ideas of how to handle the stinky problem other than the dehumidifier? The basement is sealed well. We have a sump pump that never runs. I only heard it go on once during hurricane Irene (we are in upstate NY). There are no obvious leaks. I think it gets musty because of where we live and the amount of precipitation we get. There are some ground level windows. Maybe I should work on sealing those better. Could they be the culprit?
Huh, that sounds like a problem that will be harder to fix, since you have already explored the obvious culprits. But I do think that ultimately the dehumidifier is an expensive band-aid to what is probably a deeper issue in your home. I'm not an expert on these things, but one thing I've read is to tape a piece of plastic on your floor and possibly your walls. Wait a day or two, and if there is moisture between the surface and the plastic that means it is seeping through the concrete. Is it possible you have mold or mildew growing somewhere down there? It can even grow underneath paint.
Also, be sure that all the gutter water is directed away from the home. I've also read that flower beds against the house can cause water damage and seepage, but I'll be damned if I'll get rid of mine in front of my house!
We get lots of precipitation here in the Midwest, but I can't say my basement remains permanently musty. We have a sump pump, but that's about it. But I imagine that your home's location (and how water drains in the near vicinity) can influence these matters as well.
Water problems are some of the hardest problems to solve in a home. We have water damage on the plaster in our living room, and we cannot figure out the culprit. It's frustrating!