This answer, and I believe a few others, mention using water as a radiation shield. I looked around a bit, and did not find a good answer on the logistics of how you would do that. Ignoring the lift to space cost and assuming you have H2O in sufficient quantity near your space station, a number of problems remain.
How would you position it for shielding? Unless you place your water in a heated and pressurized container, the water won't remain in liquid state and will freeze solid.
Could I erect a temporary pressure tent on the outside of my habitat, position the water to let it freeze, and move on to the section behind the raw and exposed block of ice serving as my radiation shield? Would I need to cover the ice with something, to keep it from boiling off?