When traveling abroad -- or if you're just not sure if the tap water in your home is safe (perhaps there was an outage, your filters are out of date or it just looks suspect) -- consider boiling it. It's the cheapest, fastest and most effective way to purify water and remove harmful pathogens and bacteria. And it's simple: Just fill a teakettle with cold tap water and bring it to a boil for one minute. Remove it from heat and allow it to cool. Even in countries where drinking tap water can be questionable, this method is one foolproof way to purify water.