What is a National Primary Drinking Water Regulation?

A National Primary Drinking Water Regulation, NPDWR or primary standard, is a legally-enforceable standard that applies to public water systems. Primary standards protect drinking water quality by limiting the levels of specific contaminants that can adversely affect public health and are known or anticipated to occur in water. Additional information on national primary drinking water regulations is available at http://water.epa.gov/drink/standardsriskmanagement.cfm.