ANSI/NSF Standards for Drinking Water Treatment Units

These standards represent only some of the many standards established by NSF for domestic drinking water systems.

Standard 42: Aesthetic Effects

This standard primarily deals with Chlorine removal, appearance and Taste and Odor claims.

Chlorine

A chlorine reduction claim means the system reduces the concentration of chlorine in the water. This category is broken down into classes that represent a certain level of Chlorine removal.

Class I - 75% or greater Chlorine reduction
Class II - 50% - 74% Chlorine reduction
Class III - 25% - 49% Chlorine reduction

Particulates

A performance claim for Particulate removal means the system removes particles of a certain size based on the following classes:

Class I - Reduces 85% of particles 0.5 to < 1 microns in size
Class II - Reduces 85% of particles 1 to < 5 microns in size
Class III - Reduces 85% of particles 5 to < 15 microns in size
Class IV - Reduces 85% of particles 15 to < 30 microns in size
Class V - Reduces 85% of particles 30 to < 50 microns in size
Class VI - Reduces 85% of particles equal to or greater than 50 microns in size

Standard 53: Health Effects

This standard is concerned with contaminants that may pose a health risk such as:

Lead
Volatile Organic Compounds (V.O.C.'s)
Inorganic Chemicals
Cysts
Radon
Turbidity
Pesticides and Herbicides
Trihalomethanes (THM's)
Volatile Organic Chemicals (V.O.C.'s)

A performance claim for V.O.C. reduction means the system reduces the concentration of all of the following contaminants. Some of these chemicals can be tested individually for performance claims.

Cysts

A performance claim for cysts indicates the system reduces the concentration of parasitic cysts by at least 99.95%. The cysts included in this claim are Cryptosporidium, Giardia, Toxoplasma and Entamoeba.

Turbidity

A claim for turbidity reduction means the system removes fine particulate matter that makes water appear cloudy to a level below the U.S. EPA Maximum Contaminant Level.

Lead

A performance claim for lead reduction demonstrates the system's ability to reduce the concentration of lead below the U.S. EPA Maximum Contaminant Level.

Standard 58: Reverse Osmosis Systems

alachlor • 1,2-dichloropropane • styrene • atrazine • cis-1,3-dichloropropylene • 1,1,2,2-tetrachloroethane • benzene • dinoseb • tetrachloroethylene • carbofuran • endrin • toluene • carbon tetrachloride • ethylbenzene • 1,2,4-trichlorobenzene • chlorobenzene • ethylene dibromide (EDB) • 1,1,1-trichloroethane • dibromochloropropane (DBCP) • heptachlor • 1,1,2-trichloroethane

o-dichlorobenzene • heptachlor epoxide • trichloroethylene • p-dichlorobenzene • hexachlorobutadiene • trihalomethanes (THMs) • 1,1-dichloroethane • hexachlorocyclopentadiene • m-xylene • 1,2-dichloroethane • lindane • o-xylene • trans-1,2-dichloroethylene • methoxychlor • p-xylene • 1,1-dichloroethylene • pentachlorophenol • 2,4-D • cis-1,2-dichloroethylene • simazine • 2,4,5-TP(silvex)

This standard is concerned with the performance of Reverse Osmosis drinking water systems. the performance claims are for the following contaminants:

Arsenic Reduction • Asbestos Reduction • Barium Reduction • Cadmium Reduction • Copper Reduction • Cyst Reduction • Fluoride Reduction • Hexavalent Chromium Reduction

Lead Reduction • Mercury Reduction • Nitrate Reduction • Radium 226/228 Reduction • Selenium Reduction • TDS Reduction • Trivalent Chromium Reduction • Turbidity Reduction • VOC Reduction