Water pump runs when not using water

I had that problem once and it turned out to be the water heater drain plug was leaking about a teaspoon an hour. It never leaked enough to drip on the ground, just a little puddle inside the cover. Probably evaporated faster than it was leaking. May not be your problem but something to check if it continues. Also have had a leak so small you had to run your hand over the fitting to feel the moisture but was enough to cause the pump to cycle periodically.

Running on the pump once in awhile is a good idea just to make sure you don't have a hidden leak someplace.