those in the know

Can you wear the heart rate strap ( the part that goes around your chest) in the water?
I need to have my heart rate monitor for the bike and it would be way simplier to put the chest strap on before the swim and not have to fiddle with it in T1- not willing to "test" it though since I am close to the 1/2 IM and don't want to have to replace it so soon before the race.
If you can't wear it in the water- anyone one have any tips for getting it on quickly/efficiently?
Thanks a bunch
tam