I've noticed water in my bilge lately - my first thought was that it was a bit of overflow from the fresh water tanks (which i've had happen in the past), mixed with some light rain and my bi monthly washdowns traveling down the mast, etc.
I use a wet dry to suck the bilge dry, when I do have some water there.  So, I almost always leave the bilge completely dry.
Today, I realized that it must be coming from elsewhere because the volume of water was up to where it must have engaged my float switch.  I hadn't been on my boat for about two weeks, so a bit of water wouldn't have alarmed me.
So, I dried it out and worked my way toward the stern drying along the way...  the furthest abaft I found any water was around the galley thru-hull.  So, I dried it out well.  About an hour later, there was a small puddle there.  I dipped my finger in and gave it a taste - salty. 
I made sure my hand was dry and felt around - the seacock seemed to be dry.  The moisture started around the thru-hull itself.  Although it could be coming from further abaft, I didn't see any evidence in the engine compartment.  So... I'm concerned that it's the thru-hull itself.
My big question is:  How urgent of a problem?  I think it's urgent because it's my boat, but maybe I'm just paranoid.  Do I have it hauled tomorrow?  Or can it wait a week or two? Secondary question is - if not terribly urgent, will sailing her put more stress on that thru-hull? (been planning a much needed cruise this weekend).  Is it best to have someone with more knowledge than I come take a look before hauling my boat out?  I am going to investigate more tomorrow -- but I'm fairly confident in my diagnosis.  Would love any insight from anyone with a similar experience...