Over the past few weeks, I've noticed a creaking sound coming from the bottom bracket area on my Viscount road bike. It has a Sugino BB with caged ball bearings. Yesterday, I pulled the cranks to check it out, and sure enough, the BB spindle felt gritty and hard to turn. After unscrewing the adjustable cup, I found water inside. Not just a little bit either, there was a puddle of standing water inside the BB shell. I wiped out the water and old grease, and repacked it with lots of fresh grease, but I'm worried that water will get in again, as I ride in the rain often.

I have heard of people drilling a hole in the BB shell to allow water to drain out, and am wondering if anyone has advice for drilling. What size hole works best, and what is the best place to drill it?

Any other ways to keep the BB free of water and rust, aside from overhauling it after every ride?