No. I've traveled enough down here to know what to do. Plus in this day and age bottled water is everywhere.
Another bit of advice is to not eat salads because of the water used in washing the lettuce. I'm staying in a pretty nice place though so that's not a concern.
You will notice all the Mexicans drink their sodas with no ice though. I just stick to beer and wine and it's not a problem!
I met a gorgeous girl from Argentina and we're having dinner tonight. I'll have a full report on your desk in the morning!