Glossary - Contaminants, Tastes and Odors

The contaminants discussed are not necessarily in your water. The information provided is simply designed to give you a general sense of water issues and is not intended to be complete or to give the impression that your water is unhealthy.

The effects, according to the EPA, of Short-term and Long-term exposure to levels of a contaminant that EXCEED the EPA’s Maximum Contaminant Level (MCL) or Maximum Residual Disinfectant Level (MRDL) are discussed below.

Acidic/Corrosive water. Low pH. Water with a pH under 7 can corrode your metal plumbing, giving the water a metallic taste, cause blue-green stains on your sinks, tubs and toilets, and damage/discolor your hair. Acidic water can leach unwanted metals, including lead and copper, from your piping, shorten the useful life of your appliances, plumbing fixtures and water heater, and eventually cause pinhole leaks in your piping.  

Arsenic enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. It can be found as Arsenic 5 and 3. It is odorless and tasteless.

Non-cancer issues: Thickening and discoloration of the skin, stomach pain, nausea, vomiting, diarrhea, numbness in hands and feet, partial paralysis, and blindness.

Long-term: Skin damage or problems with circulatory system, and may have an increased risk of cancer. Linked to cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate.

Chlorine, used to disinfect the water, has a MRDL of 4 ppm, and may give the water an off taste and odor. Chlorine can be breathed in, absorbed through your skin, discolor your hair and can make your hair and skin feel dry. It can also corrode certain types of water heaters.

Short-term: Chlorine can cause eye/nose and respiratory irritation or stomach discomfort.

Chloramine, used to disinfect the water, may give the water an off taste and odor. Chloramine is formed when ammonia is added to chlorine. Chloramine can discolor your hair and can make your hair and skin feel dry. It can also degrade the rubber washers and gaskets in your faucets, showerheads, washing machine hoses, etc., creating little black specs in your water. It can also corrode certain types of water heaters.

Long-term: Chloramine can cause eye/nose irritation, stomach discomfort, and anemia. 

Chlorides, above certain levels, can give your water a salty taste.

Chlorine dioxide, used to disinfect the water, has a MRDL of 800 ppb, and may give the water an off taste and odor. Some infants and young children who drink water containing chlorine dioxide in excess of EPA's standard could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorine dioxide in excess of EPA's standard.

Long Term: Some people may experience anemia.

Chlorites - Disinfection by-product: Some infants and young children who drink water containing chlorite in excess of EPA's standard could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorite in excess of EPA's standard. Some people may experience anemia.

Copper - Naturally occurring and can also come from the water corroding your plumbing, causing blue-green stains and a metallic taste. 

Short-term: Copper is an essential nutrient, but at high doses it has been shown to cause stomach and intestinal distress.

Long-term: Liver and kidney damage, and anemia. People with Wilson's Disease should consult their personal doctor if the amount of copper in their water exceeds the action level.

Corrosive water can corrode your metal plumbing, giving the water a metallic taste, cause blue-green stains on your sinks, tubs and toilets, and damage/discolor your hair. Corrosive water can leach unwanted metals, including lead and copper, from your piping, shorten the useful life of your appliances, plumbing fixtures and water heater, and eventually cause pinhole leaks in your piping. 

Cysts/Parasites - If your water comes from a reservoir, or is sometimes open to the elements, there is a possibility of cysts, i.e., Giardia and Cryptosporidium, being present. Cysts come from warm-blooded animals living near surface waters. Cysts are resistant to Chlorine and difficult to filter out because of their small size (1-6 microns. A micron is 1/25,000ths of an inch. The edge of a dollar bill is about 100 microns thick.) Cysts can cause gastrointestinal illness, i.e., diarrhea, vomiting, cramps.

Dirt, Rust and Sediment can plug faucets, toilet valves, showerheads, etc. They can cause abrasion of the internal workings of faucets and showerheads and wear them out. Rust Particles can also give the water a metallic taste and ruin laundry.

Distribution piping materials - Asbestos-lined Cement. Cast Iron. Ductile Iron. PVC. Steel. Certain municipal distribution piping may contain iron that can release rust particles, cause the water to be discolored, cause orange/brown stains, and ruin laundry. 

Asbestos fibers have been used in cement pipe for town water distribution piping. The MCL for asbestos is 7 MFL, or 7 Million Fibers per Liter. That's 1.6 Million Fibers per 8 oz glass of water. The major sources of asbestos in drinking water are decay of asbestos-lined cement water mains and erosion of natural deposits. 

Long-Term: An increased risk of developing benign intestinal polyps. 

EPA – Environmental Protection Agency.

Fluoride is naturally occurring and is sometimes added to the water.

Short-term: Staining or pitting of teeth.

Long-term: Increased likelihood of bone fractures in adults, and may result in effects on bone leading to pain and tenderness.

HAA5s are disinfection byproducts that form when Chlorine reacts with organic matter in the water, i.e., dead vegetation. HAA5s can evaporate out of the water into the air. People can be exposed to disinfection by-products, including HAA5s, from other uses of water besides drinking, i.e., showering, bathing, running the dishwasher, doing laundry, etc.  

Long-term: Increased risk of cancer. 

Hardness and Hard Water Scale. Hardness, above certain levels, can cause white/gray staining on your plumbing fixtures, tubs, showers, etc. , and make your hair and skin feel drier. Hardness scale can cause you to use up to 30% more energy to heat your hot water and can clog the inside of your water using appliances, i.e., ice maker and dishwasher. Hardness can cause you to use significantly more detergents/cleaners and cause your clothes to wear out prematurely. 

Hydrogen Sulfide (H2S), above certain levels, produces a rotten egg odor.

Iron, above certain levels, can cause orange/brown staining on your clothes and plumbing fixtures and give your water a metallic taste. It can also settle inside your hot water tank and cause issues.

Lead can leach from plumbing of older buildings and is harmful if inhaled or swallowed. Long-term: Infants and children who drink water containing lead in excess of the action level of 15 ppb could experience delays in their physical or mental development. Children could show slight deficits in attention span and learning abilities. Adults who drink water containing lead over many years could develop kidney problems or high blood pressure.

Manganese can cause brown/black staining on your hair, clothes and plumbing fixtures and give your water a metallic taste. It can also settle inside your hot water tank, making it less efficient. 

MCL - EPA’s Maximum Contaminant Level.

MRDL – EPA’s Maximum Residual Disinfectant Level.

Micron - A unit of length equal to 1/25,000ths of an inch. The edge of a dollar bill is about 100 microns thick.

MTBE - MTBE is a member of a group of chemicals commonly known as fuel oxygenates. Oxygenates are added to fuel to increase its oxygen content. MTBE is used in gasoline throughout the United States to reduce carbon monoxide and ozone levels caused by auto emissions. MTBE replaced the use of lead as an octane enhancer in 1979. Methyl tertiary-butyl ether (MTBE) is a flammable liquid used as an additive for unleaded gasoline and has leaked into the groundwater from underground gasoline storage tanks. People can be exposed to MTBE by breathing contaminated air and drinking contaminated water. 

Long-term: Still being studied. 

Nitrates/Nitrites – The greatest use of Nitrates is in fertilizer.

Short-term: Serious illness and sometimes death. The serious illness in infants is due to the conversion of nitrate to nitrite by the body, which can interfere with the oxygen-carrying capacity of the child’s blood. This can be an acute condition in which health deteriorates rapidly over a period of days. Symptoms include shortness of breath and blueness of the skin. 

pH. Acidic/corrosive water. Low pH. Water with a pH under 7 can corrode your metal plumbing, giving the water a metallic taste, cause blue-green stains on your sinks, tubs and toilets, and damage/discolor your hair. Acidic water can leach unwanted metals, including lead and copper, from your piping, shorten the useful life of your appliances, plumbing fixtures and water heater, and eventually cause pinhole leaks in your piping.  

The pH of the water can also be above 7, or alkaline.

PPB – Parts Per Billion.

PPM – Parts Per Million.

Perchlorate - Perchlorate is both a naturally occurring and man-made chemical that is used to produce rocket fuel, fireworks, flares and explosives. Perchlorate can also be present in bleach and in some fertilizers.

Perchlorate may have adverse health effects because scientific research indicates that perchlorate can disrupt the thyroid’s ability to produce hormones needed for normal growth and development.

PFAS, PFAS6, and PFOA/S are fluorinated organic chemicals. PFAS is a group of chemicals that includes the sub-group PFAS6, which includes PFOA and PFOS. They have been used to make carpets, clothing, fabrics for furniture, paper packaging for food and other materials (e.g.,cookware) that are resistant to water, grease or stains. They are also used for firefighting at airfields and other industrial uses. Between 2000 and 2006, production of PFOA and PFOS was voluntarily reduced or eliminated in the U.S. and globally by major manufacturers, although there are a limited number of ongoing uses.  

Long-term: Exposure to PFAS, PFAS6, PFOA and PFOS over 70 parts per trillion may result in adverse health effects, including developmental effects to fetuses during pregnancy or to breastfed infants (e.g., low birth weight, accelerated puberty skeletal variations), cancer (e.g.,testicular,kidney), liver effects (e.g., tissue damage), immune effects (e.g., antibody production and immunity), thyroid effects and other effects (e.g., cholesterol changes).
 

Pesticides and Herbicides:

Atrazine – Herbicide.

Long-term: Cardiovascular system or reproductive problems.

Simazine – Herbicide.

Long-term: Problems with blood.

Pharmaceuticals can be excreted by humans, flushed down the toilet/drain and end up in streams and groundwater. It is difficult and/or cost prohibitive to reduce these contaminants at the water treatment plant.

Long-term: Still being studied.

Radium – Erosion of natural deposits. 

Long Term: Increased risk of cancer.

Radon - Naturally occurring radioactive gas that can cause lung cancer and stomach cancer.

Reduces vs Removes  -  Throughout this website you will see the term “Reduces” when referring to contaminants in the water. No filter removes all of a contaminant all of the time for all of its life. Therefore, it is inaccurate to use the term “Removes”.  "Reduces" is the term that should be used.

Sulfate, above certain levels, can give your water a salty taste.

Tetrachloroethylene – Discharge from factories and dry cleaners.

Short-term: Detrimental effects to liver, kidney, and central nervous system. 

Long-term: Detrimental effects to liver, kidney, and central nervous system and can cause cancer.

THMs, Trihalomethanes, are disinfection byproducts that form when Chlorine reacts with naturally occurring organic material, i.e., dead vegetation. THMs can evaporate out of the water into the air. People can be exposed to disinfection by-products, including THMs, from other uses of water besides drinking, i.e., showering, bathing, running the dishwasher, doing laundry, etc. 

Long-term: Liver, kidney or central nervous system problems and increased risk of cancer. 

TDS, Total Dissolved Solids, above certain levels, can cause staining and give your water a salty taste.

Turbidity is a measure of the cloudiness of water. It is used to indicate water quality and municipal filtration effectiveness.

Uranium – Erosion of natural deposits.

Long Term: Increased risk of cancer, kidney toxicity.