Contaminant Testing Procedures

Water treatment products must reduce a specific amount of a contaminant effectively in order to earn NSF certification for that purpose. The table below shows the contaminants for which testing is currently available, along with the reduction amount needed in order to earn certification for that reduction claim.

Influent: The influent column lists the average amount of the substance that is added to the water at the beginning of testing.

Effluent: The amount shown in the effluent column represents the maximum amount of the substance that can be present in the treated water. A percentage indicates the minimum percentage reduction necessary to achieve certification.

Substance Average Influent Maximum Effluent (or) % Reduction Required
1,1,1-trichloroethane 0.6 mg/L 0.2 mg/L
1,1,2-trichlorethane 0.015 mg/L 0.005 mg/L
1,1-dichlorethylene 0.021 mg/L 0.007 mg/L
1,2,4-trichlorobenzene 0.21 mg/L 0.07 mg/L
1,2-dichloroethane 0.015 mg/L 0.005 mg/L
1,2-dichloropropane 0.015 mg/L 0.005 mg/L
2,4,5-TP (silvex) 0.15 mg/L 0.05 mg/L
2,4-D 0.21 mg/L 0.07 mg/L
Alachlor 0.04 mg/L 0.002 mg/L
Arsenic (Pentavalent) 0.05 mg/L 0.01 mg/L
Arsenic (Pentavalent) 0.3 mg/L 0.01 mg/L
Arsenic (Total - distillers only) 0.3 mg/L 0.05 mg/L
Asbestos 107 to 108 fibers/L 99%
Atenolol 260 ± 20% ng/L 39 ng/L
Atrazine 0.009 mg/L 0.003 mg/L
Barium 10 mg/L 2 mg/L
Benzene 0.015 mg/L 0.005 mg/L
Bisphenol A 2,200 ± 20% ng/L 330 ng/L
Cadmium 0.03 mg/L 0.005 mg/L
Carbamazepine 1,400 ± 20% ng/L 210 ng/L
Carbofuran 0.08 mg/L 0.04 mg/L
Carbon tetrachloride 0.015 mg/L 0.005 mg/L
Chloramine 3 mg/L 0.5 mg/L
Chlordane 0.04 mg/L 0.002 mg/L
Chloride 800 mg/L 250 mg/L
Chlorine 2 mg/L 50%
Chlorobenzene 2 mg/L 0.1 mg/L
Chromium (hexavalent) 0.3 mg/L 0.1 mg/L
Chromium (trivalent) 0.3 mg/L 0.1 mg/L
Chromium (hexavalent & trivalent) (Std 53, 58) 0.3 mg/L 0.05 mg/L (hexavalent) 0.05 mg/L (trivalent)
Cis-1,2-dichloroethylene 1.4 mg/L 0.07 mg/L
Copper 3 mg/L 1.3 mg/L
Cyst (dust) (RO only) Minimum 50,000/mL 99.95%
Cyst (Live or Microsphere) Minimum 50,000/L 99.95%
DEET 970 ± 20% ng/L 145 ng/L
Dibromochloropropane 0.004 mg/L 0.0002 mg/L
Dinoseb 0.021 mg/L 0.007 mg/L
Endrin 0.006 mg/L 0.002 mg/L
Estrone 23 ± 20% ng/L 3.5 ng/L
Ethylbenzene 2.1 mg/L 0.7 mg/L
Ethylene dibromide 0.001 mg/L 0.00005 mg/L
Fluoride 8 mg/L 1.5 mg/L
Fluoride (distillers only) 8 mg/L 2 mg/L
Hardness 342 mg/L 17.1 mg/L
Heptachlor (H-34, heptox) 0.08 mg/L 0.0004 mg/L
Heptachlor epoxide 0.004 mg/L 0.0002 mg/L
Hexachlorocyclopentadiene 0.15 mg/L 0.05 mg/L
Hydrogen sulfide 1 mg/L 0.05 mg/L
Ibuprofen 320 ± 20% ng/L 48 ng/L
Lead 0.15 mg/L 0.01 mg/L
Lindane 0.002 mg/L 0.0002 mg/L
Linuron 81 ± 20% ng/L 12 ng/L
Meprobamate 430 ± 20% ng/L 64 ng/L
Mercury 0.006 mg/L 0.002 mg/L
Metolachlor 1,600 ± 20% ng/L 240 ng/L
Methoxychlor 0.12 mg/L 0.04 mg/L
Methyl tert-butyl ether (MTBE) 0.015 mg/L 0.005 mg/L
Naproxen 80 ± 20% ng/L 12 ng/L
Nitrate plus nitrite
Nitrate
Nitrite
30 mg/L
27 mg/L
3 mg/L
10 mg/L
10 mg/L
1 mg/L
Nonyl phenol 1,040 ± 20% ng/L 156 ng/L
O-dichlorobenzene 1.8 mg/L 0.6 mg/L
Particulate, Class I particles 0.5 to <1 μm At least 10,000 particles/mL >= 85%
Particulate, Class II particles 1 to <5 μm At least 10,000 particles/mL >= 85%
Particulate, Class III particles 5 to <15 μm At least 10,000 particles/mL >= 85%
Particulate, Class IV particles 15 to <30 μm At least 10,000 particles/mL >= 85%
Particulate, Class V particles 30 to <50 μm At least 1,000 particles/mL >= 85%
Particulate, Class VI particles 50 to <80 μm At least 1,000 particles/mL >= 85%
P-dichlorobenzene 0.225 mg/L 0.075 mg/L
Pentachlorophenol 0.01 mg/L 0.001 mg/L
Perchlorates 0.130 mg/L 0.004 mg/L
Phenytoin 190 ± 20% ng/L 28 ng/L
Polychlorinated biphenyls (PCBs) 0.01 mg/L 0.0005 mg/L
Radium 226/228 25 pCi/L 5 pCi/L
Radon 4000 pCi/L 300 pCi/L
Selenium 0.1 mg/L 0.05 mg/L
Simazine 0.012 mg/L 0.004 mg/L
Styrene 2 mg/L 0.1 mg/L
Sulfate 800 mg/L 250 mg/L
TCEP 4,700 ± 20% ng/L 705 ng/L
TCPP 5,100 ± 20% ng/L 765 ng/L
Tetrachloroethylene 0.015 mg/L 0.005 mg/L
Toluene 3 mg/L 1 mg/L
Total dissolved solids (non-reverse osmosis, non-distiller devices only) 1500 mg/L 500 mg/L
Total dissolved solids (reverse osmosis only) 750 mg/L 187 mg/L
Total dissolved solids (distillers only) 1000 mg/L 10 mg/L
Toxaphene 0.015 mg/L 0.003 mg/L
Trans-1,2-dichloroethylene 2 mg/L 0.1 mg/L
Trichloroethylene 0.3 mg/L 0.005 mg/L
Trihalomethanes (TTHM) 0.45 mg/L 0.08 mg/L
Trimethoprim 13 ± 20% ng/L 2 ng/L
Turbidity 11 NTU 0.5 NTU
Volatile Organic Chemicals (VOCs) 0.3 mg/L 95%
Xylenes 30 mg/L 10 mg/L
Zinc 10 mg/L 5 mg/L

Units of measurement:

  • mg/L – micrograms per liter. One mg/L is the equivalent to one part per million (ppm), which would be the same as one drop out of one million drops of water.
  • ng/L - nanograms per liter. One ng/L is the equivalent of 1/1000th of a microgram per liter, which would be the same as 1 ounce in 7.5 billion gallons of water.
  • NTL - Nephelometric turbidity unit, a measurement of water's clarity. Less than 1 NTU is desirable for drinking water.
  • pCi/L - pico curies per liter, a common unit of measurement for radon gas in both air and drinking water. Less than 4.0 pCi/L is recommended for indoor air, while less than 4000 pCi/L is recommended for drinking water.

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