When you buy a bottle of water, most of the cost is for the plastic. But what about the environmental cost? Manufacturing, filling, labeling, shipping, storing and disposing of water bottles is expensive. Let's follow the life of this water bottle from beginning to end.

The majority of plastic bottles are made from polyethylene terephthalate (PET) plastic, produced from crude oil. Not only does oil extraction release greenhouse gases and harm habitats, but plastics production also casts toxins into the environment. After the oil has been extracted it is transported to refineries like this one near Cologne, the largest oil processing plant in Germany.

Distilled oil is shipped to a manufacturer, who creates tiny plastic pellets. Bottle producers then melt down these pellets into "pre-forms" that look resemble plastic test tubes. Water bottling companies heat and expand these pre-forms to shape and size their bottles as desired. In recycling, plastic bottles are melted back down and returned to pellet form.

In the bottling plant, plastic pre-forms are expanded to size, sterilized and filled with water, before being capped, labelled and packed into cases for shipping. At this bottling plant in the German region of Saxony, 1.5 million liters of water and soft drinks are bottled and packaged every day.

Bottles can also be made of bioplastic, which is produced from plant materials like corn or sugarcane instead of petroleum. Such plastics are biodegradable and can be tossed in the compost after use - but this doesn't necessarily mean they're earth-friendly. Production of bioplastic requires large amounts of resources like water, and agricultural land that could be used to grow food.

It also takes resources to transport bottled water - more than a liter of gasoline per bottle, in some cases. The Earth Policy Institute estimates that about one in four bottles of water crosses at least one international border by boat, train or truck before being consumed. All this transport emits carbon dioxide, contributing to climate change.

According to Pacific Institute estimates, producing one bottle of water takes three times that same amount of water. Also, in areas where bottling plants are located, concentrated water extraction can lead to a drop in the water table, making local communities suffer from water shortages.

By some estimates, around 60 million plastic bottles were recycled in Europe last year - just more than half of all bottles used. The rest end up as litter, getting dumped in landfills or waterways - where they take hundreds of years to decompose. Plastic waste in oceans is a major environmental problem, polluting the water and threatening sea creatures and birds.

There's a deposit on plastic water bottles in Germany. People bring their empty bottles to supermarkets and get their deposit back at machines like this one: 25 euro cents ($0.33) per bottle. The customer can get cash or a voucher for store credit. Any store that sells plastic bottles is obliged by law to accept returns for reuse or recycling.

The USA is the world's largest consumer of bottled water. But China is catching up - every year, tens of billions of plastic bottles are produced and consumed in China alone, using around 18 million tons of crude oil. As the demand for bottled water grows with China's economy, huge mountains of bottles like this one build up to be sorted for recycling.

Recycled bottles are shredded and melted back into pellets, then sold to companies that make recycled plastic products. One of the most popular products is fleece, used in clothing and blankets. After all the energy a plastic bottle consumes over its life cycle, what was once a cool gulp of water can then end up as a warm sweater.