There is a world of difference between a water filter system and a water purification system. Water filters like the Brita pitcher filters take out most nasty tastes, as well as suspended matter and some things like giardia and other ‘bugs’, but not necessarily germs/bacteria, etc. Only water purification systems remove dangerous pathogens like E. coli and worse. The cheap way to purify is to boil the water for a specified time, and then filter or treat with chlorine or other chemicals. There are “tabletop” or portable water purification systems, but they may not be inexpensive. There is a really good discussion here: https://en.wikipedia.org/wiki/Portable_water_purification
1 Like