Thanks for the article. Boiling water gets rid of pathogens. Filtering water gets rid of particulates. Getting rid of dissolved minerals like lead and so on needs a little more work. If you really want "pure" water a distillation unit is great but then again doing that gets rid of all the dissolved calcium, magnesium, and dissolved ions which can be good for heath :)
Personally I'd filter the water first and then boil to make tea. Get something tasty and purified water out of the mix :)
That boiling process is really good in purifying water.