Sure, but just because it's chock full of Hydrogen, which happens to be about the same mass as a neutron and thus takes up a lot of its energy per collision. Plastic, being a hydrocarbon, does the same thing.
That being said, water is pretty cool. You could use 2 inches of lead to stop 90% of gamma radiation, or 2 feet of water for the same effect. On top of that, metal is terrible at slowing neutrons (due to metal not being hydrogen), but that same 2 feet of water will slow down the neutrons by about 99.5%.