I have often wondered what it was like to drown. I have held my breath long enough to hurt, but I could never hold it long enough to drift away. Water is unpredictable and when you're under its silence is calming. I have always loved the water, the silence it brings, nothing compares to it. It sounds like a good way to go.
When you drown, I believe it will hurt. It will hurt because you're denying your body that what it needs. But without oxygen, anyone would dream away. Once that happens, the pain will end. Peace will flood into you with the water that enters your lungs.