IF you live in the great frozen north... one of the things often overlooked when winterizing is the water pump inlet filter and housing. It can crack if overlooked,
I've never had your problem.
BUT... I have had some screws on the water pump work a bit loose (high vibration area) and the result was it sprayed water all over when it was running, this greatly increases consumption.. I finally figured it out and tightened it down but the water runs out the hole in the floor into the wet bay and then onto the ground so it's hard to spot.. I had the access panel open for some reason when it happened and saw it.