If you travel in remote areas of the United States and Canada, a water filter, or more precisely a "microfilter," is considered adequate protection. In these original landscapes, human flow is relatively low, protozoa (such as Cryptosporidium and Giardia) and bacteria (such as Escherichia coli and Salmonella) are considered as the main threats. Any water borne virus harmful to human beings is mainly transmitted through human feces. So where there are fewer humans, we assume that the risk of the virus is also low.
It's important to make sure that your microfilter is used to handle water quality in remote areas. Some of the water filters on the market are designed to remove unpleasant smells from tap water. The village level microfilter can remove pollutants below 0.2 μ m, and shall comply with the standards and protocols of EPA's microbial purifier (for bacteria and protozoa removal) test guide or NSF protocol p231.
When should I use the water purifier?
If you are in an underdeveloped country where the water treatment and sanitation infrastructure are poor, and / or people do not have good sanitation habits near the water supply, water purifiers are a safer option. Common viruses include norovirus and hepatitis A. In order to fight against these viruses, Microfilters plus detergents like chemical pills are also a powerful option.
It is important to remember that while chemical treatment, UV and boiling can inactivate microorganisms, they do not remove particles from the water. Particles in water can hinder the effectiveness of ultraviolet rays and, to a lesser extent, impede the effectiveness of chemicals. This is a big advantage of mechanical pump water purifier.
The mechanical pump water purifier shall actually remove pollutants below 0.02 μ m, and all water purifiers shall meet the same test standards for all three types of microorganisms mentioned above.