protecting wooden countertop in the bathroom. Seal with CPES (Clear Penetrating Epoxy Sealer), then follow up with two wiped-on coats of a marine varnish such as Epifanes. This way the wood is sealed and protected fairly well, without a super thick film. But I would also be sure to wipe up ANY standing water, just to be safe.
Finish for a Bathroom Vanity? - The Wood Whisperer