Any hairsticks of mine that are finished with enamel or are natural bone are water resistant as far as the sticks go.  I wear mine in wet hair all the time.  I would avoid letting metal findings, pearls, some gemstones or roses sit in wet hair, tho.

I would *not* put any of the sticks that are dyed black during the manufacturing process (as opposed to finished in black acrylic and sealed with enamel by me) in wet hair, especially if you're blonde.  Because they are not sealed, they can shed a bit of color if they get wet.