I asked about a Mexican hotel. In answering that question someone mentioned a place that didn't have purified water. This surprised me because although I think the person was attempting a kindness, I don't think about water in Mexico much anymore.
I'm 62 and I grew up in San Diego with many trips to Tijuana. I had my adventures with bad water and\or food but I haven't had any for the last 20 years. I've come to think of the old advice like "don't take ice in your drink" and "drink only bottled drinks" as not being relevant.
Sersol1, the exact, narrow question is, do you worry about the quality of the Guadalajara water? I would not mind hearing from other people who live in Guadalajara but I would like to avoid the "I went to Guadalajara for a week and . . . " stories.