Alternative solutions for potable water

Here is a fascinating radio report on a researcher who figured out that you could make dirty water potable simply by putting it in the sun for a few hours.  He then tried to spread this technique in areas of the world where people didn't have a piped connection to potable water, and the report follows his successes and frustrations (mainly frustrations) in this quest.  You should listen to it to get the whole story, but basically it seems like, where people don't have access to wells, they'd rather have a piped system for clean drinking water installed, or if they do have piped water or wells but it's not clean, they'd rather improve their existing system to make it potable.  The researcher's solution of putting bottles in the sun is fine as a temporary fix, but it's less practical for a lot of people than the other temporary fix of boiling your drinking water.  And as for a long-term fix, it seems like people would prefer to invest their own resources and their political voice in getting a decent water system like I have where I live, instead of settling for drinking dirty water, even if it's been sterilized by the sun.