Some of the better purification methods include the activated carbon and reverse osmosis. The best contribution that carbon makes to filtration is its ability to reduce chemical quantities, poor taste, odors and many pollutants. Because carbon is only mildly effective in filtering out particulates and microorganisms, it is mostly used as a second or third stage filter in home and portable water use. It is seldom used as a stand-alone filtering, and often times, used in conjunction with reverse osmosis. Reverse osmosis, which uses a semipermable membrane filter to separate the water from contaminants.

Reverse osmosis is highly effective in removing several impurities from water such as total dissolved solids, turbidity, asbestos, lead and other toxic heavy metals, radium, and many dissolved organic. The process will also remove chlorine, and also can remove nuclear radiation such as radioactive plutonium or strontium in the drinking water. Therefore, reverse osmosis combined with activated carbon seems to be the most advanced water purification method developed so far.