We have a waterproof electric pad on our bed. It covers the whole bed just like any other mattress pad, but heats like an electric blanket. Never had any issues, and it is advertised as waterproof. Obviously for bed wetters etc.I wear diapers at night, and do occasionally have minor leaks, with no issues. If you were to wet the bed pad nightly, and wash it often, I don't believe it would last.