We just returned from our trip last week. We filled up with water at Great Harbour - at the fuel dock. Lovely gentleman named Sherman helped with dock lines. While we got water, a few of us walked over to Rudy's (?) to pick up a few provisions. Good selection of things!
Filled up again with water at Saba before heading to Anegada (Saba wins award for grumpiest dock hands).
Finally, got water again at Leverick. We were lucky to be on an outside slip next to the hose so we filled in the morning before we departed.
The water gauge on our boat was broken so we had no way of gauging how much we were using - that's why we filled up 3 times.