I agree. I've read sugared juices at night are a main suspect.
As for bottled water the reverse osmosis process used in 'good' water removes flouride. I follow this since I have a back injury and have to avoid flouride. "Spring" water means nothing to me. As in like "where's the spring"? -it could be bubbling out of the parking lot behind some factory.
You’re right about “springs.” I cringe when I see people filling up multiple jugs from some roadside “spring” on a rural road. That stuff is quite likely to contain Giardia and other pathogens. Water from a deep well, constructed according to modern sanitary codes is much safer.