Plastic water bottles come in for a lot of stick these days, but are fairly ubiquitous in our society as people have come to expect to have water on hand.
After-all it's a fair question to ask how necessary it is to buy spring/ filtered tap water/ branded tap water in the first place when you live in a first world country with safe water. While single use plastic bottles pretty much epitomize the silliness of our throw-away culture and despite recycling a lot of plastic still makes it way into the environment and end up in places like the great pacific garbage patch.
The final bottled product also carries the embodied emissions of manufacturing the bottle, sourcing/filtering the water, transport, chilling etc etc.
One way to reduce the impact of plastic bottle is to reuse them, which for a lot of bottles isn't what they are designed for and so you risk bacterial growth and potentially degradation of the bottle over time.
So what are the alternative options for those of us who like to have a drink bottle handy? Luckily options abound with varying degrees of usefulness
1) Use drinking fountains (ok in some cities, not so good away from them)
2) If it just sits on our desk at work, why not use a glass bottle.
3) Buy a proper reusable drink bottle that won't break, leak and leach and is recyclable. You could get a proper plastic drink bottle but make sure to avoid plastics #3 and #7 as they can leach toxins into the water. An increasing popular option is to buy a steel or aluminum bottle. Reputable brands of steel/aluminum bottles includes Sigg, Nathan, Klean Kanteen and Thermos. From the customers perspective these have the advantage that they last years, shouldn't contaminate the water and are just as useful hiking in the mountains as they are on your desk.
From an environmental perspective one metal bottle is obviously worse than one plastic bottle, so what's the break even number? I couldn't find a published life-cycle analysis comparing the two, but the New York Times had a piece last year which stated that for greenhouse gasses after your metal bottle has displaced 50 plastic bottles it's better for the climate and after it has displaced 500 plastic bottles it's better for the environment in all aspects (and that wasn't including the impact producing the water present in the plastic bottles). Given how long a metal bottle last (unless you lose it) it should eventually be better for the environment.
So, if you like drinking water and you like water bottles, consider getting a steel/aluminum one and say goodbye to plastic bottles.