Water Contaminants

The following is a list of common water contaminants found in both public and private drinking water supplies across the U.S. and Canada, together with their health effects and the most appropriate treatment methods for their removal. For more information on a particular contaminant or treatment method, please click on the name of the item.

Please note: This list was compiled for research and informational purposes only. It is not intended to suggest that any of the listed contaminants are present in your water supply. Only testing by an accredited lab can identify the presence of contaminants in your water supply.

Contaminant
Name
Maximum Acceptable Level Common
Sources
Health
Effects
Most Effective Treatment Technologies
Arsenic 0.010 mg/L Natural deposits, smelters, glass, electronics wastes, orchards Skin, nervous system toxicity Reverse Osmosis
Asbestos 7 MFL (million fibers / liter) Natural deposits, asbestos cement in water systems Cancer Reverse Osmosis, Activated Carbon
Barium 2 mg/L Natural deposits, pigments, epoxy sealants, spent coal Circulatory system effects Reverse Osmosis
Bacteria / Coliform - animal & human waste, septic fields, sewage, farming various illnesses Ultraviolet
Cadmium 0.005 mg/L Natural deposits, galvanized pipe corrosion, batteries, paints Kidney disorders Reverse Osmosis
Chlordane 0.002 mg/L Leaching from soil treatment for termites Cancer Activated Carbon
Chlorine 4 mg/L Water disinfection see chlorination by-products (Trihalomethanes) Activated Carbon, KDF
Chromium-6 0.1 mg/L Natural deposits, mining, electroplating, pigments Liver, kidney, circulatory disorders Reverse Osmosis
Copper 1.3 mg/L Natural / industrial deposits, wood preservatives, plumbing Gastrointestinal irritation Reverse Osmosis, KDF
Cryptosporidium Zero Animal or human waste, contaminated food products Gastrointestinal illness Reverse Osmosis, Carbon Block (0.5 micron)
E.coli Zero Naturally occurring, human or animal wastes Gastrointestinal disorders (often severe) Ultraviolet
Fluoride 4 mg/L Natural deposits, fertilizer, aluminum industries, water additive Skeletal and dental fluorosis Reverse Osmosis
Giardia Zero Naturally occurring, human or animal wastes Gastrointestinal disorders (Beaver Fever) Reverse Osmosis, Carbon Block (0.5 micron)
Hydrogen Sulfide n/a Natural deposits Rotten egg taste and odour Iron Reduction Filter, KDF
Iron 0.3 mg/L Natural deposits Staining of laundry, plumbing, appliances Iron Reduction Filter
Lead 0.015 mg/L Pipes and solder containing lead, manufacturing, waste, natural deposits Kidney damage, nervous system disorders, high blood pressure, organ damage/failure Reverse Osmosis, Specialized Activated Carbon, Metsorb
Manganese 0.05 mg/L Natural deposits Staining of laundry, plumbing, appliances Iron Reduction Filter
Mercury 0.002 mg/L Crop runoff, natural deposits, batteries, electrical switches Kidney, nervous system disorders Reverse Osmosis, Activated Carbon
Microbiological Contaminants - animal & human waste, septic fields, sewage, farming various illnesses Various
Nitrate / Nitrite 10 mg/L Animal waste, fertilizer, natural deposits, septic tanks, sewage Methemoglobulinemia (blue baby syndrome) Reverse Osmosis
PCB 10.0005 mg/L Coolant oils from electrical transformers, plasticizers Cancer Activated Carbon
Radium 5 pCi/L Natural deposits Bone cancer Reverse Osmosis
Radon Natural deposits Cancer Activated Carbon
Selenium 0.05 mg/L Natural deposits, mining, smelting, coal/oil combustion Liver damage Reverse Osmosis
Sulfate 500 mg/L Naturally-occurring Laxative effect - gastrointestinal irritation (loose stools, diarrhea, etc.) especially in infants or individuals not acclimated to high levels Reverse Osmosis
PFOA n/a (0.4 μg/L recommended) Man-made compound found around manufacturing areas, some non stick pans, treated clothing and carpets, sealants Kidney damage, liver damage, thyroid disease, developmental disorders, reproductive issues Reverse Osmosis, Tank-Based Activated Carbon System
Total Dissolved Solids 500 mg/L Erosion of naturally occurring mineral deposits Gastrointestinal irritation in some individuals Reverse Osmosis
Toxaphene 0.003 mg/L Insecticide formerly used on cattle, cotton, soybeans Cancer Activated Carbon
Trihalomethanes (THMs)(chlorination by-products) 0.08 mg/L By-product of chlorination in drinking water Cancer Activated Carbon, KDF
Turbidity n/a (1 NTU max. recommended) Soil runoff Interferes with disinfection, filtration Whole-House Sediment Filter, Reverse Osmosis
Uranium 0.03 mg/L Natural occurring Kidney disorders, cancer Reverse Osmosis
Viruses - animal & human waste, septic fields, sewage, farming various illnesses Ultraviolet
Volatile Organic Compounds (VOCs) Varied Varied Varied, incl. cancer Activated Carbon
Zinc 5 mg/L Natural deposits, industrial waste Metallic taste in water Reverse Osmosis, KDF