The filtered water may still have a taste/smell of chlorine to it. When I was fishkeeping, the recommendation was to let water sit for 24 hrs to allow the chlorine in the water to evaporate out. Maybe you can try that for a few days and see if your dog likes the house water better after it has sat for a while?
Gryffon Vom Wildhaus
BH, OB1, TR1, AD
Rottweiler/Hairy Dog mix?? 2004-2015