in additon to what VolvoFarmer said. . . piling up dirt next to a wooden structure is to (in effect) hang out the "free buffet" sign for termites in the summer. Somewhat counterproductive, no? if the structure is stone or concrete, then disregard the above, of course.
Ghurd and Nando's suggestions seem like they have the most going for them. Nando's suggestion also has the benefit of keeping the floor of the building a little warmer, too. . . which might reduce the incidence of ice on the shower floors?
I have seen (at highway rest stops, etc) drinking fountain faucets that drain below the frost line immediately after use. They seem to require a gravel drain field to WELL below frost in order to work, though.
the "keep it flowing" school of thought has some attraction to it, too. if you have some power and lack plentiful water, a small pump that recirculates the water back below the frost line (into a buried coil?) to warm up could do the same thing without losing the water. The same sort of thing is mandated for new construction in parts of california to bring hot water to distant points of use without wasting the 'cold' water already in the pipes.
the pumps I'm familiar with are equipped with magnetic drives to avoid leakage. the motors are often in the range of 1/40th horsepower or so. Similar pumps get used by the Over-Clocking crowd to drive their liquid-cooling rigs. . . . a little ingenuity and a couple Neo magnets could convert one of these to DC or wild AC power? Just a thought.
If you're on a well, one recirculation option that gets used is to just dump the circulated water back into the casing. I've heard that scenario used in wisconsin for heat pumps both in winter and summer. . . . Fine HomeBuilding Magazine did an artcle on this sort of thing about 5 years ago. Wish I could find that issue. (maybe search for it online. . . "ground source heat pumps" I think is the article title. or maybe "geo-source" yadda.)
-Dan