It may just be the airline I fly the most (CO) but the only time I've ever seen water served from anything other than a bottle in recent years was on IAH-LGW-IAH in BusinessFirst. Then it was served from a pitcher, but I could also see into the galley where the flight attendants were filling the pitchers from the water bottles.
I have no problem drinking the water on board if it's bottled. And I have heard CO flight attendants tell passengers before that the company's policy is to only serve bottled water during drink/meal service.