The chart below displays items from the list of contaminants regulated under the National Primary or Secondary Drinking Water Regulations. Across the top are the most common, commercially available methods used to treat drinking water. The chart was developed from documentation provided by the US Environmental Protection Agency, the Water Quality Association, and the American Water Works Association.
It is important to note that while reverse osmosis is generally considered effective for removal of contaminants like fecal coliform, cysts, and virus every manufacturer of typical (ordinary) RO based systems will warn their product "should not be used on microbiologically unsafe water supplies without adequate pre- or post- disinfection." This means if your community were to issue a "boil water alert" an ordinary RO system should not be trusted to remove the offending contaminant.
(This should not be interpreted to mean a PWS™ BEV-Series system is recommended to purify pond water or source water not conforming to operational specifications.)