My 15 Year Old Dog Lapps Eagerly At The Water

My 15 year old dog lapps eagerly at the water bowl, but is not getting his tongue in the water. sometimes he laps the side of the bowl, sometimes the air several inches above. I've tried colored bowl, shiney stainless bowl, ice floating in the water, showing him the water surface, all to no avail. This is a very recenc condition, he never used to have a problem. Any suggestions?