Assessment of in-home reverse osmosis systems for removing pesticides and nitrate-nitrogen from private well water

In an effort to provide homeowners with information about the use of in-home reverse osmosis (RO) water treatment systems for the removal of pesticides and nitrate-nitrogen (nitrate), the Minnesota Department of Agriculture (MDA) conducted a study to evaluate RO treatment system effectiveness. From 2017 through 2020, the MDA collected samples before and after RO system treatment from 54 private wells that were known or suspected to contain pesticides and nitrate. The average age reported by homeowners since installation, for 32 of the RO systems, was approximately 11 years and most of the homeowners (36) indicated their RO systems had been maintained (filters changed) within the last two years.