Most Common Contaminants in Water

The most common contaminants in water are microorganisms, nitrate, and arsenic. Microorganisms include bacteria, viruses, and protozoa. Giardia, lamblia, cryptosporidium, coliform, and E. coli are common kinds of bacteria.

Bacterial contamination is most likely to have originated from animal waste that has found its way into water sources through runoff. Occasionally, these bacteria will contaminate crops in the field by irrigating with water tainted with raw manure.

Nitrate is a chemical found in most fertilizers, manure, and liquid waste discharged from septic tanks. Natural bacteria in soil can convert nitrogen into nitrate. If ingested, nitrate impairs the ability of our red blood cells to carry oxygen throughout the body.

Ground water can pick up arsenic naturally in varying amounts, but it was used for decades as an insecticide and fungicide in agriculture. A continued controversial practice is to add organic arsenic to poultry feed in the U.S. to increase weight gain for human consumption.

Although organic arsenic is less toxic than pure arsenic, under some conditions it is converted to the more toxic, inorganic form.

Contaminants Removed by Carbon Filtration

Contaminants Removed by Carbon Filtration
Chemicals Organic Contaminants
Acetaldehyde 2,4,5-TP
Acetic Acid 2,4-D
Acetone Acrylamide
Alcohols Adipates (diethylhexyl)
Amines Alachlor
Amyl Acetate Aldicarb
Amyl Alcohol Aldicarb Sulfone
Antifreeze Aldicarb Sulfoxide
Benzene (“fracking” carcinogen) Atrazine (agricultural herbicide)
Bleach Benz(a)anthracene (PAH)
Butyl Alcohol Benzene (“fracking” carcinogen)
Butyl Acetate Benzo(a)pyrene (PAH)
Calcium Hypochlorite Benzo(b)fluoranthene (PAH)
Chloral Benzo(k) fluoranthene (PAH)
Chloamine Bromodichloromethane
Chloroform Bromoform
Chlorine Butyl benzyl phthalate (PAE)
Chlorobenzene Carbofuran
Chlorophenol Carbon Tetrachloride Chlordane
Chlorophyll Chloroform
Citric Acid Chrysene (PAH)
Cresol Dalapon
Defoilants (plant growth inhibitors) Dibenz(a,h) anthracene (PAH)
Detergents Dibromochloromethane
Diesel Fuel Dibromochloropropane (DBCP)
Dyes Dichlorobenzene (o-,m-)
Ethyl Acetate Dichlorobenzene (para-)
Ethyl Acrylate Dichloroethane (1,2-)
Ethyl Alcohol Dichloroethylene (1,1-)
Ethyl Amine Dichloroethylene (cis-1,2-)
Ethyl Chlorine Dichloroethylene (trans-1,2-)
Ethyl Ether Dichloromethane (methylene chloride)
Gasoline Dichloropropane (1,2-)
Glycols (“fracking” toxins) Diethylhexyl phthalate (PAE)
Herbicides Dinoseb
Hydrogen Peroxide Diquat
Hydrogen Selenide Endothall
Hydrogen Sulfide Endrin
Hypochlorous Acid Epichlorohydrin
Insecticides Ethylbenzene
Iodine Ethylene dibromide (EDB)
Isopropyl Acetate Glyphosate (Round Up herbicide)
Isopropyl Alcohol Heptachlor
Ketones Heptachlor epoxide
Lactic Acid Hexachlorobeneze
Mercaptans Hexachlorocyclopentadiene
Methyl Acetate Indeno (1,2,3-c,d) pyrene (PAH)
Methyl Alcohol Lindane
Methyl Bromide Methoxychlor
Methyl Chloride Monochlorobenzene
Methyl Ethyl Ketone Oxamyl (vydate)
Naphtha Pentachlorophenol
Nitric Acid Picloram
Nitrobenzene Polychlorinated byphenyls (PCBS)
Nitrotoluene Simazine
Odors (general) Styrene
Oil Dissolved Tetrachloroethylene
Organic Acids Toluene
Organic Esters Toxaphene
Organic Salts Trichlorobenzne (1,2,4)
Oxalic Acids Trichloroethane (1,1,1-)
PCB?s Trichloroethylene
Perchlorate (used in rocket fuels) Trichloroethylene (1,1,2-)
Pesticides Trihalomethanes (THMs)
Phenol Vinyl Chloride
Plastic Taste Xylene (total)
Propioic Acids 2,3,7,8-TCDD (Dioxin)
Propyl Acetate
Propyl Acid
Propyl Chloride
Rubber Hose Taste
Sodium Hydrochorite
Sulphonated Oils
Tar Emulsion
Tartaric Acid
Taste (DI Water)
Taste (From Organics)

Contaminants Removed by Reverse Osmosis

Contaminants Removed by Reverse Osmosis
Contaminant Average Influent (incoming) Concentration (mg/L) Average Effluent (outgoing) Concentration (mg/L) Average Percent Reduction
Arsenic 0.28 0.0035 98.7
Barium 10.2 0.207 97.9
Cadmium 0.036 0.0005 98.6
Chromium (Hexavalent) 0.15 0.013 91.3
Chromium (Trivalent) 0.17 0.01 94.1
Copper 3.1 0.03 99
Cysts 149357 #/ml 5 #/ml 99.99
Turbidity 10.2 0.26 97.5
Fluoride 8 0.5 93.9
Lead 0.15 0.002 98.6
Radium 226/228 25 pCi/L 5 pCi/L 80
Selenium 0.1 0.008 92
Other Total Dissolved Solid (TDS) contaminants are reduced by up to 98%: Aluminum, Ammonium, Bicarbonate, Calcium, Chlorine, Chromate, Cyanide, Ferro cyanide, Iron, Magnesium, Mercury, Manganese, Nitrate, Phosphate, Silicate, Silver, Sodium, Strontium, Sulfate, Sulfite, Thiosulfate, Zinc.
Note: Your results may vary depending on the regularity of your maintenance, the general condition of your unit, and the contamination-level of the water supply.

Contributors to System Performance

Even the best reverse osmosis systems won’t always filter out everything 100%. There are several factors for this, but the best way to maximize your systems performance, is to change the filters out for new ones, at recommended intervals.

This is why it’s recommend to change your water filters frequently, and definitely no later than a filters recommended service period.

  • Contaminant level of the incoming water supply.
  • Whether or not a sediment filter is used, if incoming water has large particles, such as from a well.
    Type of prefiltration (granulated-carbon, carbon-block, activated or not).
  • Size of pores in the RO membrane (the smaller, the better).
    How well the system is maintained (how often the filters are changed).