Water glossary of terms

Abrasion occurs in water-using equipment when particles in water come in contact with other components, such as pumps and valves. Continued abrasions may result in problems with the component. Basic mechanical (sediment) filtration will remove most abrasive particles.


Asbestos was used in cement water pipes in the early 1900s, and since it occurs naturally in rock, it is commonly found in water supplies near mining operations. Asbestos is linked to several types of cancers. Indications are that most asbestos exposure is by inhalation rather than ingestion; however the EPA has established an MCL for asbestos fibers in water. Filters rated for asbestos reduction will lessen this health threat.

One-celled organisms that are present in everything from water to food. Bacteria can be found in virtually any water system. Municipal water systems check for harmful bacteria levels on a regular basis. A water filtration system certified Class I for particulate reduction by NSF is a simple and cost-effective way to remove particles 1/2 micron in size and larger. Most bacteria are larger than 1/2 micron.

A filtration system with this claim means that the system limits the passage and/or growth of heterotrophic bacteria so that the bacterial population of the product water is no greater than that of the incoming water. Hetertrophic bacteria are considered safe for the general population, but they can cause taste and odor problems.


Activated carbon mixed with chemical binders to form a hard block of carbon, which is then cut and shaped to fit the filter housing. Sediment removal is dependent on the micron rating. Higher carbon content removes odors and off-tastes. There are submicron carbon block filters that remove smaller-sized particles, providing cyst reduction. These filters must be handled carefully as they can crack, causing an undetectable by-pass.

Often the aftermath of the two step ammonia plus chlorine disinfection method used at large, central municipal-type treatment plants. They can produce a disagreeable taste and odor. Chloramine removal is limited to physical adsorption methods such as filtration using activated carbon.


Chlorine is a disinfectant which wipes out bacteria and is added to most all municipal water systems. Chlorine may produce undesirable taste and odor in drinking water, such as a "swimming pool" taste. The actual health danger comes from some of the chemical compounds chlorine forms by combining with organic molecules that can be found in water. Activated carbon is the best solution to reducing chlorine in water.

A waterborne parasite that causes severe stomach cramping, fever, vomiting and diarrhea that can last from 10 to 14 days in a healthy person. It can be fatal for persons with immune deficiencies (eg. infants or the elderly). Hundereds of thousands of people are sickened each year when this parasite is present in the water. Cryptosporidium can be found in virtually any surface water source. Very fine filtration (submicron) is required for protection from this contaminant. Be sure to look for NSF Standard 53 on the filters you purchase.

Chlorine-resistant "capsules" which contain parasites that, if ingested, may cause disease with symptoms of severe abdominal cramping and diarrhea. These parasites can be particularly dangerous for anyone with a comprised immune systems, such as HIV or cancer patients. Cysts include Cryptosporidium, Giardia, Toxoplasma and Entamoeba. Very fine filtration (submicron) is required for protection from cysts. Be sure to look for NSF Standard 53 on the filters you purchase.


A one-celled, microscopic parasite that lives in the intestines of people and animals. It is responsible for an illness known as giardiasis. It causes severe stomach cramping, fever, vomiting and diarrhea that can last from four to six weeks in a healthy person. This is the most common waterborne parasite. Those with weakened immune systems are particularly vulnerable to this cyst. Very fine filtration (submicron) is required for protection from this contaminant. Be sure to look for NSF Standard 53 on the filters you purchase.

Granular activated carbon (GAC) filters consist of a housing filled with loose activated carbon granules. The activated carbon (AC) surface attracts and holds molecules such as those that cause poor tastes and odors. Better GAC systems can reduce other contaminants, such as lead. But, these lower-priced systems do not "fine-filter" the water and therefore are not as effective as other products in removing particulates and cysts.

Water that has picked up minerals such as calcium and magnesium as it travels through certain types of rock and soil. Approximately 85 percent of the country has hard water. hardness is measured in both parts per million (ppm) and grains per gallon (gpg). Anything more than one gpg or 17.1 ppm qualifies water as "slightly hard." It is the minerals in water that can eventually form scale deposits in water-using equipment.

Also referred to as "sulfur water", hydrogen sulfide causes the rotten-egg smell sometimes present in drinking water. it is an acid which can cause rapid corrosion of all types of plumbing materials. The only good remedy is chemical oxidation followed by filtration.

Lead is a heavy metal that has gained a great deal of attention from the EPA, which in 1991 imposed new standards for lead levels in drinking water that are 10 times more protective than levels previously thought to be safe. It is estimated that 40 million Americans currently drink water containing more lead than the limit set by the EPA. Lead poisoning can cause mental retardation adn birth defects. Basic filtration rated for lead reduction will offer protection.

A common gasoline additive that has been found to leak into ground water supplies and contaminate drinking water. It is made of methanol and a by-product of the oil-refining process. The EPA has classified MTBE as a possible carcinogen. Basic filtration rated for MTBE reduction will offer protection.

The independent testing agency that sets product standards for water filtration manufacturers, established its Drinking Water Treatment Unit Certification Program to determine if a water filtration system performs in the marketplace as tested. NSF International is known around the world for the development of independent standards, product testing and certification services in public health, safety and protection of the environment.

Many things can contribute to bad smelling and tasting water such as chemicals, organic matter, and the condition of the water distribution system. If your water smells or tastes like a "swimming pool," it is probably due to chlorine that has been added for disinfection. Although chlorine is very effective at killing harmful bacteria and viruses, it frequently causes both an off taste and odor. The addition of ammonia to produce monochloramine (which lasts longer in the pipes) makes the taste and odor even worse. One of the most effective treatments for bad tasting water is a filter containing activated carbon.

pH is the chemical shorthand for how acidic or alkaline your water is. A pH of "7" is considered "normal" and neither acidic nor alkaline. If your water is below "7" it is acidic and the risk of lead or other metals in the water goes up. If it is above "7" it is alkaline and will have a greater tendency for scale to form.

A very reliable way to remove dirt, particulate contaminants, chlorine and off-tastes and odors. Submicron filtration can remove cysts like Cryptosporidium and Giardia. The unique preocoat design consists of a membrane folded over a drainage grid, which supports a coat of adsorptive Micro-Pure® powder, a proprietary blend of powdered activated carbon and other filtering materials. Precoat filters provide a longer filter life and remove 99.99% of all particles 1/2-micron and larger. Precoat filtration is exclusive to Everpure.

RO systems use pressure to force water molecules through a membrane, causing contaminants to be left behind and separated from the water. These systems are very effective, especially for removal of heavy metals, nitrate, fluoride, and pesticides, but they are more expensive both in terms of equipment, maintenance costs, and water usage than other systems. They are also limited in their ability to produce water over a given period of time. Due to these critical factors, it is very important to verify that your water quality requires RO.

This is the term that's used when minerals, usually calcium and magnesium are deposited over time in water-using equipment and appliances. Scaling has the potential to block tubing and pipes, interfere with proper operation, and reduces the overall life of equipment. Many treatments exist to control or eliminate scale buildup in water-using equipment. How "hard" the water is and how the water will be used will determine which treatment will be most effective.

Water softeners condition the water through an ion exchange process. In other words, a softener exchanges sodium ions for calcium and magnesium ions. Softeners are sometimes confused with filtration, but are primarily used to reduce the mineral content (hardness) in water to prevent scale buildup. They do not produce "ingredient" water, free of off-tastes and odors, particulates, certain other contaminants and cysts.

Trihalomethanes are formed when chlorine reacts with organic matter in water, such as from decaying leaves. They have been linked to a higher incidence of cancer. A filter with activated carbon rated for THM reduction is an effective treatment.

Total Dissolved solids are not visible to the naked eye. However, when water is frozen, ice cubes may look cloudy.

Cloudiness that results from suspended particles of dirt in the water. These particles usually are in two categories: larger, visible pieces that can easily be filtered out; and minute, invisible particles that can make water hazy. The more minute the particles, the finer the filter required.

VOCs are a group of water contaminants that can be very dangerous if found in drinking water at unsafe levels. They include some of the most common, most toxic, and most widely distributed water contaminants. Examples include pesticides, herbicides, or insecticides that seep into the ground. VOCs are usually the result of pollution and originate from areas of industrialization. This category also includes total trihalomethanes. A filter with activated carbon rated for VOC reduction is an effective treatment.

WQA is an independent non-profit organization that provides the water treatment industry with quality assurance. WQA awards their Gold Seal to only water treatment products that have been tested to meet or exceed industry standards for performance, capacity, and integrity in removing a variety of water supply contaminants.


Call for pricing and quantity discounts.
(321) 783-6565