We realize that not everywhere in Central and South America has unsafe drinking water.  But we also know that many places do. We didn't like the idea of chemical sanitizers like bleach or buying all of our drinking water. So we needed some sort of filtration system.  All of the RV filtration systems we could find were mainly for filtering chemicals and metals and for improving taste.  Not for sanitizing.  We eventually found a company called that makes a variety of different types of filters, and they had one that I thought I would be able to rig up under the sink in-line with our plumbing.  It's called the "Sawyer 3 way in-line filter".  It is a .1 micron filter which will remove everything except viruses and amoebas. Also, the filter never needs to be replaced.  You just have to back flush it every so often.  It comes with handy little quick release clips so I can take it out and flip it around in seconds to do this.  I was a little worried that it might reduce the water flow at the sink but I can't tell any difference now that it's in.  It took about $15 of various hoses and adapters to get it in place and we now have safe drinking water from just about any source. We'll probably take a steripen as well for particularly sketchy sources.