Water Quality Glossary

Water that contains substances that lower the pH value below 7.0 (neutral).

The capacity for neutralizing an alkaline substance.

Water that contains substances that raise the pH value above 7.0 (neutral).

The capacity for neutralizing an acid.

acute, chronic
Bacteria in water can cause immediate symptoms of flu or intestinal distress. Such acute illnesses are generally of the highest priority among water utility managers, who are less concerned with longer-term, poorly understood chronic disorders that result from exposure to metals, industrial chemicals, and pesticides. Acute cases are rarely fatal, and thousands of U.S. cases of water-based ailments such as cramps, diarrhea are probably never reported to physicians.

An underground body of water that is more protected from contaminants than surface water, but is still susceptible to perils such as fecal coliformfrom septic tanks. Half of all Americans get drinking water from such underground sources. Of these, roughly a third have their own wells, which are not regulated by government. The remainder use municipal water systems, which draw on underground supplies that are subject to the same rules as surface water.

action levels
With some contaminants, the [EPA] does not establish hard and fast levels allowed in water supplies, but does set a course of events for the most extreme cases.  Lead is an example of a water pollutant that has noprimary or secondary standards but does have an action level that is calculated on a community-wide basis.

Single-cell organisms that can reproduce in the human gut and cause vomiting and diarrhea, bacteria also cause acute health problems that can kill AIDS and cancer patients. See chlorine, fecal coliform, protozoan.

blue-baby disorder
A possibly acute disorder also known as methemoglobinemia that despite its name, turns blood cells brown.  Nitrates from fertilizers lock up hemoglobin in an infant’s bloodstream, displacing the oxygen. If left untreated, the condition can be fatal.

Chloride imparts a salty taste, and can indicate contamination from sea water, brackish water, or salt storage.

Chloride may make your water taste salty and indicates contamination from an outside source such as salt storage, seawater, or septic waste.

chlorinated pesticides
Commonly used agricultural pesticides. Some people who drink water contaminated with these compounds could experience problems or damage to the eyes, liver, kidneys, or spleen and may have an increased risk of getting cancer.

Gamma BHC (Lindane)
Alpha Chlordane
Gamma Chlordane
Heptachlor Epoxide

coliform bacteria
Indicates contamination from an unsanitary condition such as septic waste or surface water entering the water supply. Health effects include gastrointestinal illness, cryptosporidium and giardia lamblia.

Determines the coloration level. MCL – 5 units.

Usually associated with the corrosion of copper pipes. Can cause stomach or gastrointestinal illness, liver and kidney damage and anemia.

A protozoan one-half as large as a red blood cell, cryptosporidium is so small and tough that it is very hard to detect, much less kill. It causes acute health problems in healthy individuals and may be fatal to individuals whose immune systems are compromised by illness, old age, or medical treatments. See protozoan.

Indicates washwater contamination. MCL – 0.5 mg/L.

To water experts, disinfection is a general process to kill living organisms. It does not refer to the removal of unwelcome chemical compounds in the water supply.

Distillation refers to the boiling of water to make steam, which is then collected and condensed for drinking. It’s expensive because of the amount of energy it uses. Distillation is available as point-of-use or -entrysystem. Some pollutants are concentrated by distillation.

environmental estrogens
These are man-made chemicals, including PCBs, dioxin and triazines, that can cause chronice reproductive and behavioral problems in animals. The molecules of environmental estrogens are chemically similar to natural hormones and trigger subtle hormonal changes, especially in the fetus in early stages of human development. The effects in man are still much disputed by scientists. Some researchers believe these chemicals are responsible for learning disabilities, attention-deficit disorder, breast cancer, and low sperm counts. See the book [Our Stolen Future] for more information.

fecal coliform
Bacteria from excrement, fecal coliform are not necessarily harmful by themselves, but are indicative of the presence of other disease-causing organisms that may cause diarrhea, vomiting, or a more serious illness.

fecal streptococcus
These are another group of bacteria that indicate human or animal waste. In some situations, these bacteria survive better than Total or Fecal Coliform. Therefore, they are useful as an indicator of human or animal waste contamination.

filtration, flocculation, sedimentation
Filtration is the process by which water is forced through sand beds. Flocculation is the process by which chemicals are added to the water, causing tiny clumps of debris to form. Sedimentation is the process of removing the flocculate matter.

first draw
This term refers to water that has been sitting in pipes or plumbing fixtures overnight and is first drawn when taps are opened in the morning. Such samples will usually have the highest levels of lead contamination. In homes with severe lead problems, first-draw readings for lead may be three times as high as purged-line samples. See purged line.

Added to many municipal water supplies, also found naturally. Excessive levels may damage teeth.

A meaningless, unregulated word used to describe a source of bottled water, according to Food and Drug Administration rules.

A common sales ploy in the home water-filter industry: A technician will place a goldfish in your tap water when he arrives at your home. One hour later, the goldfish will be dead from chlorine. But the significance to human health, according to most experts, is minimal, since most humans do not breathe through gills.

This acronym stands for granulated activated carbon, an inexpensive treatment technology by which water passes through grains of carbon. Compared with more expensive solid-block models, GAC filters sometimes affect mostly the taste and smell of water.

ground water
Water from a well or underground acquifer.

Calcium and magnesium are the main hardness minerals. Although hardness is not a health threat, excessive levels may be harmful to plumbing fixtures and pipes. White deposits around faucets and on dishware are often caused by excessive hardness.

health advisory level (HAL)
The amount of a contaminant which may indicate a long-term potential for chronic health problems if discovered by a local water treatment plant, but which poses no immediate acute danger. See MCL.

It has recently come to our attention that hemochromatosis is an often overlooked ailment. If you have any experience with hemochromatosis and iron in drinking water, please contact us at stump2@pipeline.com

immune system
The immune system is the body’s way of identifying and destroying diseases, intruders, or foreign cells. The immune system weakens with age, and during medical treatments for some cancers and organ transplants. Persons with Acquired Immune Deficiency Syndrome (AIDS) can have particularly weakened immune systems that are vulnerable to organisms such as cryptosporidium.  The EPA and the Centers for Disease Control (CDC) advise people with such immune deficiencies to boil their water.

Usually comes from a natural source. High levels of iron may cause a bad taste in the water and cause severe staining of laundry and plumbing fixtures. Excessive iron can be a health risk to people with a medical condition known as hemochromatosis.

Usually comes from corrosion of pipes and plumbing fixtures. Causes numerous health disorders and reduced IQ scores. Our packages contain a double lead sample that includes a “first draw” and a “flushed line” sample. This helps to determine where the lead is coming from.

Naturally occuring metal. Not usually considered a health threat. Can cause brownish-black stains on laundry, dishes, and fixtures.

maximum contaminant level (MCL)
The MCL is the amount of a water contaminant which must be reported to state authorities if discovered by a local water treatment plant .

maximum contaminant level goal (MCLG)
The MCLG is the desired, targeted amount of a contaminant allowed in water which the EPA hopes to be able to achieve in the future.

Methyl tertiary butyl ether (MTBE) is a chemical added to gasoline to promote cleaner combustion. As a result of leaking underground storage tanks and pipelines, as well as recreational lakes, MTBE is increasingly being found in drinking water sources.

A meaningless, unregulated word on bottled-water labels, according to Food and Drug Administration rules.

Comes from natural decay of organic matter and agricultural runoff. Nitrate causes decreased oxygen carrying capacity in infants and some adults. This can lead to methemoglobinemia (blue baby syndrome). High levels of nitrate indicate possible contamination from agriculture and suggest the need for pesticide testing.

Similar to nitrate, however nitrite can cause decreased oxygen carrying capacity in anyone.

nonpoint source of pollution
These are wastes that come from so many sources over such a wide area that they are impossible to pinpoint or regulate. In the spring planting season, wastes from agricultural fields and livestock are a significant source of cryptosporidium, triazines, and nitrates. But suburban lawn chemicals also qualify as nonpoint wastes. Well-meaning attempts to control nonpoint pollution have failed, at least so far, because of an independent mindset in farmers and anti-environmental sentiments in Congress.

Determines the odor level. MCL – 5 units.

A meaningless, unregulated word on bottled-water labels, according to Food and Drug Administration rules.

These are oxygen molecules that are much-used by the bottled water industry to remove the taste of chlorine in water, as well as to provide additional purification.

Environmentally persistent compounds that were used in electronic components and some well pumps. They can cause an increased cancer risk.

Arochlor 1016
Arochlor 1221
Arochlor 1232
Arochlor 1242
Arochlor 1248
Arochlor 1254
Arochlor 1260

Indicates whether water is acidic or basic. Acidic water can cause corrosion of plumbing and fixtures, which leads to elevated levels of metals such as lead and copper. High pH can cause scaling of the plumbing system.

point-of-use or -entry
These are two terms the plumbing industry uses to describe the equipment homeowners use to filter their own water. Point-of-use filters, typically used in the kitchen, apply to water used only for drinking. Point-of-entry devices, often placed in the basement, treat water that is used throughout a home.

primary or secondary standards
The EPA divides contaminants into many lists, charts and tables. Some contaminants are dubbed primary, while others are labeled secondary. But the only contaminants that require immediate notification of the public are bacteria and nitrates. Water systems will have to send a report to their consumers once a year.

Protozoans are organisms, such as cryptosporidium that have a life-cycle with several stages, some of which allow them to pass through a chlorine disinfection process unharmed.

A meaningless, unregulated word on bottled-water labels, according to Food and Drug Administration rules.

purged line
A faucet that has been opened and allowed to run for a specified length of time, usually 1-5 minutes.

Radon is a naturally occuring radioactive gas. The worst exposure to radon probably occurs when a person takes a shower.

reverse osmosis
Reverse osmosis is a [purification] process by which water flows over a membrane that blocks contaminants. Reverse osmosis membranes must be cleaned periodically or replaced. This technology wastes significant amounts of water. Reverse osmosis is available as a point-of-use or -entry system.
spring water
According to the U.S. Food and Drug Administration, spring water is water that comes out of the ground on its own or is bottled near water that comes out of the ground on its own.

surface water
Water from rivers and lakes. Roughly half of all Americans get drinking water from surface water sources. See ground water.

Naturally occurring but can indicate outside contamination of the water supply. Causes gastrointestinal discomfort in individuals who are not accustomed to drinking the water.

In toxicology (the study of poisons), synergy describes a process by which two or more contaminants or toxins combine to pose a cancer risk several hundred or even several thousands of times higher than each pollutant might pose by itself. The exact mechanisms of synergy are unknown. In a recent experiment with yeast, the synergistic effects of a variety of contaminants suggested that scientists barely understand how the modern cocktail of chemicals present in water affects the human body, a potentially alarming prospect for water engineers. For now, all contaminants are regulated individually, as that is the way scientists traditionally calculate public health threats. In the real world, each of us is exposed not just to one contaminant, but to tens of thousands. See environmental estrogens.

trace metals
Trace metals may come from industrial contamination or natural deposits. They can cause increased cancer risk, damage to organs and changes in blood chemistry.


Triazines are herbicides, or weed killers, that are used on a variety of U.S.crops, including grains and citrus. Triazines are currently present in both ground and surface waters. They’re banned in Europe; the U.S. Environmental Protection Agency is reviewing two triazines–atrazine and simazine–but is unlikely to ban them. These and other triazines are a cheap way for farmers to kill a wide range of weeds.

trihalomethanes (THMs)
Trihalomethanes are byproducts of chlorine, which is used to disinfect water, and carbon-based plant debris in the water. Chloroform is the best known example. THMs cause 10,000 cases of colon and bladder cancer annually. The chlorine industry strenuously opposes closer regulation of THMs.

To water engineers, turbidity means cloudiness. Turbidity in water can be harmless, or it may indicate to water engineers that extra filtration, flucculation, and sedimentation is needed.

This is an emerging disinfection technique that uses ultraviolet (UV) light. It’s a promising technology, but UV isn’t applicable to murky waters that the light cannot penetrate.

Compounds which are found in many household products, paints, petroleum products and industrial solvents. People who drink water containing these compounds in excess of the MCL could experience damage to liver, kidneys, spleen, or circulatory system, or changes in the blood. There is also an increased risk of cancer associated with most of these compounds.

Regulated VOC’s:
carbon tetrachloride
vinyl chloride

Trihalomethanes (Total):

Unregulated VOC’s:
1,1 -dichloroethane
1,2 -dichlorobenzene
1,2,3 –trichlorobenzene

waivers, exemptions
Official permission granted by state or federal officials to avoid monitoring for a water pollutant.

PEACH Inspections provides Water Quality Testing in Chester county, Montgomery county, Delaware County, Berks County, Lancaster County, and Bucks county


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