Last night I was awoken a couple of times by a loud noise coming from what sounded like under my bedroom. The noise was mechanical sounding (kind of a humming or buzzing) that began abruptly lasted about 2-3 seconds, and then stopped. When it stopped, I heard the drain in the bathtub gurgle a little. This happened 2 or three times in the night ... and I think I just heard it again (although I'm in a different room now). Here's some additional information: (1) I've lived in the house since August, through various weather conditions, and haven't heard the noise before; (2) it was raining a lot (but not as much as it has before) last night; (3) the house has a crawl-space and possibly (though I've never seen it) a sump pump; (4) we ran the dishwasher before bed, but the sound also occurred much later at night/early this morning and the dishwasher seems to be empty and through it's cycle; (5) my wife heard the sound too (so I wasn't just "hearing things").
Any ideas of what it could be??? Do I just need to get under the house and investigate? What could cause the humming/buzzing plus the water gurgling?
Thanks for any suggestions! ~d.