Good to see you got to sleep in until 5 this morning!
Just a thought on the water idea. At one point long ago when I lived somewhere else I had bought a new outdoor water dish that was rubber. I was thinking it would be a good idea for Minnesota Winters. It wouldn't crack and once the water had froze that it would be easy to pop out and refill. Well, he hated drinking out of it. He'd wait and drink out of the one in the house like he hadn't had a drink in a week. After switching dishes he was fine. The rubber dish ended up being used for dry dog food. There must have been something in the rubber dish that made the water taste funky.
Another water favoring thing that's happened in my house is the dogs preferring my aquarium water (or pond tubs outside) over nice fresh water in their dishes. (You should see the fronts of my aquariums that are on bottom shelves of the racking! Slobber drools!) I used to laugh and say they (I have 3 dogs now) preferred fish flavored water. I started to think about it and how I use water to do water changes on my aquariums. For aquariums I age the water. Basically I let the water set out for a day before using it in the aquariums. By doing that it allows the water to do what is called degassing. I've always hated the taste of my water and thought I'd try degassing a gallon on the counter for a day and see if the taste changed. It actually did. Before I was changing their water a couple times a day and giving them fresh water. It wasn't getting drank much. I've started putting degassed water in their inside dish and they now are leaving my aquariums alone (most of the time).
I don't know if you have city water or well water, but well water is more likely to contain higher sulfur gas levels, as well as others, and city water has chlorine and chloramines added to the water. Chlorine will dissipate during the degassing along with other trapped gasses. Chloramine you're stuck with, unless you feel like neutralizing it with aquarium conditioners all the time. (I don't think I'd be quite that ambitious.)
You could try an experiment using 2 dishes of water (use dishes he knows are okay to drink from or it may skew the results). In one dish use fresh tap water and the other use aged water that's set out for a day. See if he shows a preference. Just an idea. Who knows. Maybe Smyrna's water just is better.