Most of the bottles I have seen are meant to filter for taste and microorganisms as well. The problem with making non-potable water into potable water is that the sub-micron filtration that is required creates a large pressure drop and slows the flow down considerably. In addition, the filters have a much shorter useful life. You really don't need anything more than carbon filtration in most cases assuming all you want is healthier, better tasting water.
Whenever anyone asks me about water filtration or bottled water (a topic with which I am particularly familiar) I usually give the same advice. Dollarwise, convenience-wise, tastewise and healthwise the best option for most people is a point of use (countertop or under the counter) carbon filter at the kitchen sink. They are basically a plastic or metal housing that is designed to hold an industry standard filter.
Dollarwise: you can produce high-quality water for a penny a gallon or less in most cases. Much, much cheaper than bottled, PUR or Brita filtered.
Convenience-wise: point of use filtration allows you to quickly filter as much or as little water as you need at that time. The vast majority of water people ingest comes from the kitchen sink. A filter there allows you to filter not only your drinking but your cooking water as well.
Tastewise: the majority of what people refer to in municipal water as a "bad taste" is organic or chlorine. This is easily removed at a high efficiency with simple, cheap, carbon filtration. Well water is a different matter and requires a different approach. Assuming that your municipal water is ok to begin with all that most people need to do is run it through a carbon filter.
Healthwise: again, most of the compounds of concern for adults are easily filtered with carbon. If you have children (or even if you don't) you may want to opt for a filter that removes lead or flouride depending on your concern. Brita type filters do not filter nearly as well as a standard cartridge.
First step is to find a housing. I use one like this but there are many types available including chrome ones. Under the sink are easy to install and work just as well if you have aesthetic concerns with the countertop type.
Then you pick a filter. Here is a listing of cartridge types:
http://www.home-water-purifiers-and-filt...ilters.php For most people I recommend coconut based carbon blocks. Coconut carbon tends to produce the best tasting water. Carbon block is not prone to tunneling like granular carbon is.
FIlters like this used to be sold in MLM schemes for hundreds of dollars. Now on the internet you can get a housing and filter for <$50. I have given filters to each of my family members as gifts and they love them. The difference is so noticible that whenever you drink unfiltered water it will taste bad. If you do a side-by-side comparison you will wonder how you ever lived without a filter.
I know this sounds like a commercial but this is one of things that you want to tell other people because it makes such a big difference. Try it, you'll like it.
Sorry I didn't answer your original question.
BT
PS- the site above for the housing is just an example that I found with a quick search. The site with the filters is where I order my replacement filters as they had the best prices that I could find last time I looked.
