Diabetic "Weirdness"?

Jimmy seems to be doing well on his insulin - keeping a steady (and trim) weight. Seems happy and playful - actually LIKES to get his twice-daily shots. But for the last few days, he's been growling at his water dish (?!). It's not an aggressive growl - it's the same gurgly-growl he does to me to tell me he wants/needs something. It seems to be a Jimmy-equivalent of "ahem". It would typically be something he would do if the water dish was empty - to alert me that it needs to be refilled

We've been in FL for over a month, and I'll admit that the water has a high chlorine content (it's like drinking from a swimming pool, IMO - we have well water back in Michigan) - but he's been drinking this same water over a couple of winters now. I have scrubbed the bowls, given fresh water repeatedly, switched to a different location; "on the placemat" and "off the placemat" and today, bought a new bowl that is hard plastic so his tags don't *clink*. I thought that would do the trick (the new bowl) - until he walked over and growled at it a while ago. He WILL drink when he's good and thirsty; but his whole body language is "wary".

I have ruled out just about everything/anything I can think of, short of installing a compressed-carbon water filter. And Jimmy is my bullet-proof dog - NOTHING (normally) fazes him. He's fearless in the face of thunder/fireworks/vacuum cleaners/loud tools. I can't fathom why the water dish is so spooky?

Has anyone else had their dog balk at drinking chlorinated water; or does diabetes promote "weirdness"?

And Happy New Years, everyone!