To my knowledge, all owls can bath as part of their feather maintenance routine. They seem to enjoy it when they do, but I have no idea the frequency. Since birds have a few different feather cleaning methods at their disposal (water, preen oil, anting, dust baths, sunning) perhaps it changes with what kind of things they have been getting into, just as we have different cleaners for different kinds of dirt/stains.

Here is a young GHO in a photo captioned “Shake That Thing” taking advantage of a bird bath.