I'm one of those people that needs water in a container in order to drink it. If I have to get it from the tap, I just forget. So I can generate a horrible amount of waste if I'm not careful.
We've always purchased canned water for our tech writing business. I just never really got around to switching at home. Perrier is really easy to get in cans with a ring-pull, but only in multipacks. It's very surprising it's not widely available next to regular soft drinks in cans.
There's also CanO water. This is a slightly more engineered solution: as well as a normal ring-pull can, it also comes a can that you can re-seal. At first, this looks a bit over-the-top, but it kind of makes sense; you can refill the can from a water fountain, just like you would a bottle, so it's genuinely reusable. The whole can (including the plastic seal) is also recyclable.
CanO water is available from Ocado, Tesco, and Morrisons, apparently. I've not yet seen it on the shelf, but will make a point of buying some if I do.
Isn't it Madness to Buy Canned Water?
Yep, canned water sounds like a real luxury product, but compared to water in plastic, it feels kind of acceptable.