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National Primary Drinking Water Standards Primary (Health Related) Inorganic Contaminants

See Also: Water Treatment Terms & Definitions

ContaminantsMCLGMCLWQA Recommended Treatment MethodsPotential Health Effects from Ingestion of WaterSources of Contaminant in Drinking Water
Antimony 0.006 mg/L 0.006 mg/L -Coagulation/Filtration
-Submicron Filtration
-Reverse Osmosis
-Ultrafiltration
-Distillation
-Cancer -Fire retardants
-Ceramics
-Electronics
-Fireworks
-Solder
Arsenic (+3) 0.05 mg/L 0.05 mg/L (Interim Standard) -Chemical Oxidation/Disinfection
-Reverse Osmosis
-Distillation
-Skin Damage
-Nervous system toxicity
-Natural deposits
-Smelters
-Glass
-Electronic wastes
-Orchards
Arsenic (+5)     -Coagulation/Fiiltration
-Submicron Filtration
-Anion Exchange
-Activated Alumina
-Reverse Osmosis
-Distillation
-Electrodialysis
   
Arsenic (organic complexed)     -Activated Carbon    
Asbestos (fibers > 10 µm) 7 MFL 7 MFP (million fibers per liter, >10 µm) -Coagulation/Filtration
-Submicron Filtration
-Reverse Osmosis
-Ultrafiltration
-Distillation
-Cancer
-Nervous system toxicity
-Natural deposits
-Asbestos cement in water systems
Barium 2.0 mg/L 2.0 mg/L -Cation Exchange
-Reverse Osmosis
-Distillation
-Electrodialysis
-Circulatory system effects
-Nervous system toxicity
-Natural deposits
-Pigments
-Epoxy sealants
-Spent coal
Beryllium 0.004 mg/L 0.004 mg/L -Coagulation/Filtration
-Submicron Filtration
-Activated Carbon
-Activated Alumina
-Cation Exchange
-Reverse Osmosis
-Distillation
-Electrodialysis
-Bone damage
-Lung Damage
-Electrical aerospace, defense industries
Cadmium 0.005 mg/L 0.005 mg/L -Coagulation/Filtration
-Submicron Filtration
-Cation Exchange
-Distillation
-Kidney Effects -Galvanized pipe corrosion
-Natural deposits
-Batteries
-Paints
Choromium (+3) 0.1 mg/L 0.1 mg/L (total chromium) -Coagulation/Filtration
-Cation Exchange
-Reverse Osmosis
-Distillation
-Electrodialysis
-Liver Disorders
-Kidney Disorders
-Circulatory disorders
-Natural deposits
-Mining
-Electroplating
-Pigments
Chromium (+6) Same As above   -Anion Exchange
-Reverse Osmosis
-Distillation
-Electrodialysis
   
Chromium (organic complexes) Same As above   -Activated Carbon    
Copper 1.3 mg/L 1.3 mg/L (action level) -Cation Exchange (20%-90%)
-Reverse Osmosis
-Distillation
-Electrodialysis
-Gastrointestinal irritation -Natural/industrial deposits
-Wood preservatives
-Plumbing
Cyanide 0.2 mg/L 0.2 mg/L -Chemical Oxidation/Disinfection
-Anion Exchange (20%-90%)
-Reverse Osmosis
-Distillation
-Electrodialysis
-Thyroid Damage
-Nervous system damage
-Electroplating
-Steel
-Plastics
-Mining
-Fertilizer
Fluoride 4.0 mg/L 4.0 mg/L -Activated Alumina
-Bone Char
-Reverse Osmosis
-Distillation
-Electrodialysis
-Skeletal & dental florosis -Natural deposits
-Fertilizer
-Aluminum industries
-Water additive
Lead zero 0.015 mg/L (action level) -Cation Exchange(20%-90%)
-Coagulation/Filtration
-Submicron Filtration/Activated Carbon
-Reverse Osmosis
-Distillation
-Electrodialysis
-Kidney damage
-Nervous system damage
-Natural/industrial deposits
-Plumbing
-Solder
-Brass alloy faucets
Mercury (+2) 0.002 mg/L 0.002 mg/L (total mercury) -Cation Exchange(20%-90%)
-Coagulation/Filtration
-Submicron Filtration/Activated Carbon
-Reverse Osmosis
-Distillation
-Electrodialysis
-Kidney disorders
-Nervous system damage
-Crop runoff
-Natural deposits
-Batteries
-Electrical switches
Mercury (HgCl3)     -Anion Exchange(20%-90%)
-Reverse Osmosis
-Distillation
-Electrodialysis
   
Mercury (organic complexes)     -Activated Carbon    
Nickel 0.1 mg/L 0.1 mg/L -Cation Exchange(20%-90%)
-Reverse Osmosis
-Distillation
-Electrodialysis
-Heart damage
-Liver damage
-Metal alloys
-Electroplating
-Batteries
-Chemical production
Nitrate (as nitrogen) 10 mg/L 10 mg/L -Anion Exchange
-Reverse Osmosis (sensitive to pressure)
-Distillation
-Electrodialysis
-Methemolglobulinemia -Animal waste
-Fertilizer
-Natural deposits
-Septic tanks
-Sewage
Nitrite (as nitrogen) 1 mg/L 1 mg/L -Chemical Oxidation
-Anion Exchange
-Reverse Osmosis
-Distillation
-Electrodialysis
-Methemolglobulinemia Same as Nitrate;rapidly converted to Nitrate
Selenium (+4) 0.05 mg/L 0.05 mg/L (total selenium) -Coagulation/Filtration
-Submicron Filtration/Activated Carbon
-Anion Exchange
-Activated Alumina
-Reverse Osmosis
-Distillation
-Electrodialysis
-Liver damage -Natural deposits
-Mining
-Smelting
-Coal/Oil combustion
Selenium (+6)     -Anion Exchange
-Activated Alumina
-Reverse Osmosis
-Distillation
-Electrodialysis
   
Sulfate 500 mg/L (proposed standard) 500 mg/L (proposed standard) -Anion Exchange
-Activated Alumina
-Reverse Osmosis
-Distillation
-Electrodialysis
-Diarrhea -Natural deposits
Thallium 0.0005 mg/L (proposed standard) 0.002 mg/L (proposed standard) -Cation Exchange
-Activated Alumina
-Distillation
-Kidney, liver, brain, intestinal damage -Electronics
-Drugs
-Alloys
-Glass

National Primary Drinking Water Standards Primary (Health Related) Organic Contaminants

ContaminantsMCLG, mg/LMCL, mg/LTreatment Methods
Acrylamide zero 0.0005 (action level) Control of water treatment chemicals and surfaces in contact with water
Adipates (diethylhexyl) 0.4 0.4 Activated Carbon
Aeration
Alachlor zero 0.002 Activated Carbon
Aldicarb 0.007(P)* 0.007(P)* Activated Carbon
Aldicarb sulfone 0.007 (P)* 0.007 (P)* Activated Carbon
Aldicarb sulfoxide 0.007(P)* 0.007(P)* Activated Carbon
Altrazine 0.003 0.003 Activated Carbon
Benz(a)anthracene (PAH) zero (P)* 0.0001 (P)* Activated Carbon
Benzene zero 0.005 Activated Carbon
Aeration
Benzo(a)pyrene (PAH) zero 0.0002 Activated Carbon
Benzo(b)fluroanthene zero (P)* 0.0002 (P)* Activated Carbon
Benzo(k)fluoranthene (PAH) zero (P)* 0.0002 (P)* Activated Carbon
Butyl benzyl phthalate (PAE) zero (P)* 0.1 (P)* Activated Carbon
Carbofuran 0.04 0.04 Activated Carbon
Carbon tetrachloride zero 0.005 Activated Carbon
Aeration
Chlordane zero 0.002 Activated Carbon
Chrysene (PAH) zero (P)* 0.0002 (P)* Activated Carbon
2,4-D 0.07 0.07 Activated Carbon
Dalapon 0.2 0.2 Activated Carbon
Di[2-ethylhexyl]adipate 0.4 0.4 Activated Carbon
Dibenza(a,h)anthracene (PAH) zero (P)* 0.0003 (P)* Activated Carbon
Dibromochloropropane (DBCP) zero 0.0002 Activated Carbon
Aeration
Dichlorobenzene (ortho-) 0.6 0.6 Activated Carbon
Aeration
Dichlorobenzene (meta-) 0.6 0.6 Activated Carbon
Aeration
Dichlorobenzene (para-) 0.075 0.075 Activated Carbon
Aeration
Dichloroethane (1,2-) zero 0.005 Activated Carbon
Aeration
Dichloroethylene (1,1-) 0.007 0.007 Activated Carbon
Aeration
Dichloroethylene (cis-1,2-) 0.07 0.07 Activated Carbon
Aeration
Dichloroethylene (trans-1,2-) 0.1 0.1 Activated Carbon
Aeration
Dichloromethane (methylene chloride) zero 0.005 Aeration
Dichloropropane (1,2-) zero 0.005 Activated Carbon
Aeration
Diethylhexyl phthalate (PAE) zero 0.006 Activated Carbon
Dinoseb zero 0.006 Activated Carbon
Diquat 0.02 0.02 Activated Carbon
Endothall 0.1 0.1 Activated Carbon
Endrin 0.002 0.002 Activated Carbon
Epichlorohydrin zero 0.002 (action level) Control of water treatment chemicals and surfaces in contact with water
Ethylbenzene 0.7 0.7 Activated Carbon
Aeration
Ethylene Dibromide (EDB) zero 0.00005 Activated Carbon
Aeration
Glyphosphate 0.7 0.7 Activated Carbon
Heptachlor zero 0.0004 Activated Carbon
Heptachlor epoxide zero 0.0002 Activated Carbon
Hexachlorocyclopentadiene 0.05 0.05 Activated Carbon
Aeration
Indenol (1,2,3-c,d)pyrene (PAH) zero (P)* 0.0004 (P)* Activated Carbon
Lindane 0.0002 0.0002 Activated Carbon
Methoxychlor 0.04 0.04 Activated Carbon
Monochlorobenzene 0.1 0.1 Activated Carbon
Aeration
Oxamyl (vydate) 0.2 0.2 Activated Carbon
Pentachlorophenol zero 0.001 Activated Carbon
Picloram 0.5 0.5 Activated Carbon
Picloram 0.5 0.5 Activated Carbon
Polychlorinated byphenyls (PCBs) zero 0.0005 Activated Carbon
Simarzine 0.004 0.004 Activated Carbon
Styrene 0.1 0.1 Activated Carbon
Aeration
2,3,7,8-TCDD (dioxin) zero 3X10-8 Activated Carbon
Tetrachloroethylene zero 0.005 Activated Carbon
Aeration
Toluene 1. 1. Activated Carbon
Aeration
Toxaphene zero 0.003 Activated Carbon
2,4,5-TP (silvex) 0.05 0.05 Activated Carbon
Trichlorobenzene (1,2,4) 0.07 0.07 Activated Carbon
Aeration
Trichloroethane (1,1,1-) 0.2 0.2 Activated Carbon
Aeration
Trichloroethane (1,1,2-) 0.003 0.005 Activated Carbon
Aeration
Trichloroethylene zero 0.005 Activated Carbon
Aeration
Trihalomethanes (THMs)
  • Chloroform
  • Bromodichloromethane
  • Dibromochloromethane
  • Bromoform
zero 0.100 Activated Carbon
Aeration
Ultrafiltration (20%-90%)
Reverse Osmosis (20%-90%)
Vinyl chloride zero 0.002 Aeration
Xylenes (total) 10. 10. Activated Carbon
Aeration
(P)* = Proposed Standard
MCLG = Maximum Contaminant Level Goal established at the level at which no known or anticipated adverse effects on the health of persons occur and which allows an adequate margin of safety; expressed in milligrams per liter unless otherwise specified.
MCL = Maximum Contaminant Level established as close to the MCLG as feasible taking into consideration costs and treatment techniques applicable at public water systems; expressed in milligrams per liter unless otherwise specified.

National Secondary Drinking Water Regulations

Recognized Treatment Techniques for meeting the National Secondary Drinking Water Regulations with the Application of Point-Of-Use Systems

"The National Secondary Drinking Water regulations control contaminants in drinking water that primarily affect the aesthetic qualities relating to the public acceptance of drinking water. The regulations are not federally enforceable but are intended as guidelines for the states" (40 CFR Section 143.3)

For simplicity, WQA uses the term Point-Of-Use (POU) when referring to both treatment at the tap and for whole house treatment.

Except for instances of contamination through inhalation or dermal adsorption, the WQA notes that in-home treatment of drinking and cooking water only is often the most economical and preferred method of choice for reducing these drinking water aesthetic contaminants. Of course, the particular contaminant found in the water will determine the appropriate treatment technique.

The recognized treatment methods listed here reflect the fact that point-of-use systems on the market today may differ widely in their effectiveness to treat any specific contaminant. Anyone contemplating use of such point-of-use equipment for a specific application or purpose should make their selection only after careful investigation of the performance capabilities. As part of the installation procedure, the performance of the system should be verified through an appropriate water analysis. In addition, the product water should be monitored periodically to verify performance.

It is the general consensus of the manufacturers and sellers of the point-of-use systems employing the listed techniques that, if these systems are defect free, properly applied and installed, and maintained strictly according to the manufacturers' installation and maintenance instructions, they may be considered for use in meeting the requirements of the National Secondary Drinking Water Regulations (SDWR).

ContaminantSMCL, mg/LTreatment Methods
Aluminum (AL +3 ) 0.05 to 0.2 depending on case-by-case circumstances Cation Exchange
Reverse Osmosis
Distillation
Electrodialysis
Chloride (C1 -1 ) 250 Reverse Osmosis
Distillation
Anion Exchange
Electrodialysis
Color 15 color units
Anion Exchange
Activated Carbon
Filtration
Chlorination
Reverse Osmosis
Distillation
Ozonation
Activated Alumina
Copper (Cu +2 ) 1.0 Reverse Osmosis
Distillation
Cation Exchange (20%-90%)
Electrodialysis
Corrosivity Non-corrosive Calcite or Calcite/Magnesium Oxide (Magnesia)
(5 to 1) Filter to raise pH
Soda Ash Chemical Feed
Polyphosphate Feed
Sodium Silicate Feed
Reduce TDS via Reverse Osmosis (partial, split stream treatment)
Coatings
Insulating Unions
Fluoride (Fl -1 ) 2.0 Activated Alumina
Bone Char
Reverse Osmosis
Distillation
Electrodialysis
Foaming agents (MBAS)
(methylene blue active substances)
0.5
Chlorination
Activated Carbon
Ozonation
Reverse Osmosis
Distillation
Iron (Fe +2)
(ferric iron)
0.3
Filtration(oxidizing filters)
Cation Exchange
Reverse Osmosis*
Pressure Areation/Filtration
Chlorination - Precipitation/Filtration
Distillation
Electrodialysis
Iron (Fe +3 ) 0.05 Filtration

*Ferrous Iron (clear water iron) is readily converted to ferric iron (red water iron) in the presence of any air or oxidizing material; precipitating ferric iron must be prevented to avoid fouling and interference with effective reverse osmosis membrane rejection.

Manganese (Mn +2)
(ferric iron)
0.5 Filtration(oxidizing filters)
Cation Exchange
Reverse Osmosis*
Distillation
Pressure Areation/Filtration
Chlorination - Precipitation/Filtration
Electrodialysis
Manganese (Mn +4 )   Filtration

*manganese must be maintained in the soluble manganous (Mn +2) to avoid fouling and interference with effective reverse osmosis membrane rejection.

Odor 3 threshold odor number Activated Carbon
Aeration
Oxidation

Note: Chlorine and hydrogen sulfide are examples of odors that may be reduced by the treatment methods suggested.

pH 6.5-8.5 pH may be increased by alkalies and may be decreased by acids
Ion Exchange
Neutralizing Filter (Calcite, Magnesia)
Silver (Ag +1) 0.1 Coagulation/Filtration
Submicron Filtration/Activated Carbon
Ion Exchange (Anion or Cation depending on complexed Ion Species)
Sulfate (SO 4 -2) 250 Reverse Osmosis
Distillation
Anion Exchange
Electrodialysis
Total dissolved solids (TDS) 500 Reverse Osmosis
Distillation
Deionzation by Ion Exchange (Cation/Anion in two bed or mixed bed)
Electrodialysis
Zinc (Zn +2) 5 Reverse Osmosis
Distillation
Cation Exchange
Electrodialysis

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