I'm in the same "thermostatic water control won't help me, I'm in Texas" boat. Our tap water is rarely cool enough to where a water control would be useful.
Plus, the only times I really need accurate temp are for B&W film developing, and I use distilled water for pre-wash and developer and final rinse. I just stick a jug in the fridge an hour or two before I start to run the film, and mix cold distilled with room temp to get a liter of 20°. It stays stable for an hour or so, whatever I don't use goes back in the jug. I just use whatever-temp water for print processing or washing (developer in a tray gets to room temp and stabilizes by the time I'm really printing), and a tray warmer for lith developer.
I sometimes use water from our drinking water tap (filtered) and haven't had problems with that (TF-5 doesn't get the old-socks smell like it does with tap water, and our tap water can get really rusty at times). But I don't click the shutter unless I'm pretty sure I'll want to print that neg, so I don't go through piles of film and I like the security of distilled, especially for final photoflo rinse. If I ever move back to Michigan, I might want a faucet solution.