Based on the posts in anther forum… The consensus was, if you ride in wet weather a lot you probably should consider drilling a drain hole in the BB to allow the water to exit the BB. The idea was that you drain the water before it can cause any problems with the BB bearings, etc… Personally I don’t ride in the rain that often, and I can’t bring myself to drill holes in my titanium BB. So my bike has no extra holes.
Of course if you do drill a drain hole in the BB, first you should remove the BB and select a location that is lowest on the BB to allow the water to drain. And be sure to get all of the metal filings out of the BB before you reassemble it.