The bottles are made from BPA free plastic. There are other eco-friendly materials such as stainless steel but they tend to me much more expensive. The bottles are being sent to developing countries that can't afford to pay high prices and effectively. We are looking into using biodegradable materials. The WA CUP bottles can last a good year and save at least 100 single-use plastic bottles.
The tap water can make you ill but there are much cheaper, less wasteful alternatives to buying bottled water. There are clean water sources all over Asia. Many places to do water deliveries and use far less single-use plastic. Tourists are usually unaware of these alternatives.
Using any reusable bottle is better than buying disposable bottled water. However, the WA CUP is raising the awareness of the benefits of reusing bottles and helping to educate in those areas that are worse affected by plastic waste.