Here's a glossary of some terms that may be new to you:

acid - This is any substance which releases hydrogen ions when dissolved in water. An acid is the opposite of an alkali and has a pH rating lower than 7.0. Most acids react with a base to form a neutral salt and water.

acidity - This s the quantitative capacity of a water or water solution to neutralize an alkali or base. It is usually measured by titration with a standard solution of sodium hydroxide, and expressed in ppm or mg/L of its calcium carbonate equivalent.

activate alumina - Activated alumina is a filter media made by treating aluminum ore so that it becomes porous and highly adsorptive. Activated alumina will remove a variety of contaminants, including excessive fluoride, arsenic, and selenium.

alkali - This is a substance which has a pH greater than seven. It is the opposite of an acid. Highly alkaline waters tend to cause drying of the skin. A hydroxide alkali may also be called a base.

alkalinity - This is a measure of the capacity of water to neutralize an acid - how much acid can be added to water without causing a significant change in pH. Water does not have to be strongly basic (high pH) to have high alkalinity. In the water industry, alkalinity is expressed in mg/l of equivalent calcium carbonate.

anion and cation exchange - Anion exchange and cation exchange use the chemical ion exchange process to exchange anions and cations on a "resin" bed for cations and anions of the contaminant that needs to be removed from the water. Anion exchange typically uses chloride or hydroxide anions, and can be used to treat for mercury, nitrates, arsenic, and various staining agents. Cation exchange typically uses sodium or potassium chloride, and can also treat for some forms of lead and radium. It is also commonly used to soften water.

arsenic - This is a poison which shows up mainly in water supplies drawn from wells. It has been linked to several cancers and has been found to harm nerves, heart, blood vessels, and skin.

bacteria - These are unicellular microorganisms, some of which are harmful to man. Many different types of bacteria can be found in drinking water.

Birm filter – This is an aluminum silicate which is coated with manganese dioxide. It is used as an oxidizing catalyst filter medium for iron and manganese reduction.

carbon dioxide (CO2) - Carbon dioxide in water forms an acid, lowering its pH and making it corrosive. Carbon dioxide gets into water by being absorbed from the air by rain or by decay of organic matter in the earth.

(activated) carbon filtration – The filters are made of clusters of carbon atoms stacked upon one another. The carbon is activated by passing oxidizing gases through the material at extremely high temperatures. The activation process makes it a highly porous material. This, in turn, makes it very good at absorbing contaminants. The filters work by attracting and holding certain chemicals as water passes through it.

chlorination/chlorinator - A mechanical device specifically designed to feed chlorine or other solutions (e.g. hypochlorides) into a water supply.

chlorine – This is used in the disinfection of water. It is also an oxidizing agent for organic matter, iron, hydrogen sulfide, etc. In water, chlorine reacts with organics to form trihalomethanes (THM) which can cause cancer.

copper – This is a metal which, at elevated levels, can cause nausea, vomiting, diarrhea and stomach cramps. Infants under one year of age can sustain permanent kidney and liver damage if they suffer long-term exposure (more than 14 days) to elevated levels of copper.

cryptosporidium - This is a parasite from animal waste takes a dormant form, called a cyst, that has been found in water.

dechlorination – This is the removal of excess or free chlorine from a water supply. This is often done by adsorption with activated carbon or by catalytic type filter media.

deionization (DI) - The removal of the ionized minerals and salts from water. Positively charged ions are exchanged for hydrogen ions (using a cation exchange resin). Then negatively charged ions are exchanged for hydroxide ions (using an anion exchange resin). The hydrogen and hydroxide ions then unite to form water molecules.

disinfection - Disinfection technologies kill or screen-out biological contaminants present in a water supply. Chlorination, microfiltration, ozone, and ultraviolet light are examples.

distillation - Distillation produces high quality, treated water by heating the raw water until it turns to steam. The steam travels through a condensation coil, where it is cooled and condensed back into liquid form in a separate section. The contaminants remain in the boiler section, with the condensed water in the second section being substantially free of contaminants.

feed pump/chemical feeder - This is a device which introduce chemicals into a water supply in proportion to the water flow.

hardness – This is a characteristic of natural water due to the presence of dissolved calcium and magnesium. Hardness is usually expressed in grains per gallon, parts per million, or milligrams per liter, all as calcium carbonate equivalent. Water up to 1 GPG (or 17.1 mg/l) is considered soft, and water from 60 to 120 GPG is considered moderately hard. A water softener's effectiveness depends on how hard the incoming water is.

iron - This is an element which is often found dissolved in ground water. It causes staining after oxidation and precipitation, causes the taste of water to change, and causes unsightly colors (especially when it reacts with tannins in beverages such as coffee and tea).

lead - This is a metal, high levels of which in water have been linked to lower IQs in children. A low lead level on the water company's consumer-confidence report does not guarantee low levels of lead in your home. Very old homes can have lead or galvanized water piping; new homes can have lead as well--in the lead-based solder used on copper pipes or in faucets.

manganese - This is an element sometimes found in water, which can cause black stains in laundry and plumbing fixtures.

microfiltration - Microfiltration uses a filter media to physically prevent biological contamination from passing through. Ceramic and solid block carbon are commonly used to provide microfiltration.

neutralizing filter/neutralizer – These are alkaline materials such as calcite (calcium carbonate) or magnesia (magnesium oxide). They are used to neutralize acid waters, i.e., to bring its pH back to the neutral point of 7.

nitrates - These are derived from nitrogen, which occurs naturally in many different forms in the environment. When nitrogen enters soil, it is converted to nitrates by microorganisms. Plants use some of these nitrates, but dangerously high levels of nitrates in water can still result. High nitrate levels can cause methemoglobinemia - or 'blue baby syndrome' - in infants. There are also some birth defects associated with high nitrate levels. In addition, there are indications of a potential link between high nitrates in drinking water and gastrointestinal cancer and gastic cancer.

oxidation – This is a chemical process in which electrons are removed from an atom, ion or compound. Examples of oxidation include combustion and the rusting of iron.

ozone treatment - This treatment oxidizes organic contaminants in much the same way that chlorine does. An ozone generator converts the oxygen found in air to O3, or ozone. As with chlorination, proper concentrations and contact time is essential for disinfection.

point of entry (POE) equipment - This treats most or all of the water before it is distributed, either throughout a small community or at a single building. POE equipment treats for health contaminants like volatile organic compounds (VOCs) that can be absorbed through the skin, or contaminants like radon which exist as a harmful vapor suspended in the water that can be inhaled during showering. Water softeners are also typically POE.

point of use (POU) equipment - This treats water at a single tap, while the rest of the water in the building remains untreated. POU equipment is primarily used to treat health contaminants like lead, and aesthetic contaminants like sulfur which are a concern in water used for drinking and cooking.

pH (potential of Hydrogen) – This is an expression of the acidity of a solution. A pH of 1 is very acidic, a pH of 14 is very basic, and a pH 7 is neutral. The neutral point of 7 indicates the presence of equal concentrations of free hydrogen and free hydroxide ions.

resin – This is a synthetic organic ion exchange material. High capacity cation exchange resin is widely used in water softeners.

reverse osmosis - The process works by forcing water under great pressure against a semi-permeable membrane, where water molecules form a barrier that allows other water molecules to pass through while excluding most contaminants. Maintenance involves the replacement of the RO membrane cartridge every two or three years and the carbon and sediment pre-filters every six to twelve months. RO also incorporates an activated carbon filter, which can provide added treatment for the volatile organic compounds (VOCs) not treated by the membrane itself.

sulphur - A yellowish solid chemical element. Water sometimes contains hydrogen sulfide gas.

soda ash - This is the common name for sodium carbonate. It is a chemical compound used as an alkaline builder in some soap and detergent formulations. It is used to neutralize acid water. It’s also used in the lime- soda ash water treatment process.

soft water - Any water whose hardness minerals are 1.0 GPG (17.1 mg/L) or less.
ultraviolet (UV) sterilization - Modern ultraviolet treatment units use a UV bulb in a clear quartz or plexiglas housing, around which flows the untreated water. The UV light destroys the genetic material of pathogens like coliform bacteria and legionella, which effectively neutralizes them by preventing them from reproducing.

total coliform - These are bacteria whose presence in high numbers indicates that potentially harmful bacteria – for example, Escherichia coli (E. coli) – may be present.

total dissolved solids - The weight of solids per unit volume of water which are in true solution. This is usually determined by evaporating a measured volume of filtered water and measuring the residue weight. TDS is expressed as ppm per unit volume of water.

trihalomethanes (THMs) - These are a group of organic chemicals (including chloroform) that are byproducts of chlorination. They are known to cause several cancers, including bladder cancer.

ultraviolet (UV) light - Ultraviolet light has treated water since the beginning of time through natural sunlight. Modern ultraviolet treatment units use a UV bulb in a clear quartz or plexiglas housing, around which flows the untreated water. The UV light destroys the genetic material of pathogens like coliform bacteria and legionella, which effectively neutralizes them by preventing them from reproducing.

volatile organic compounds (VOCs) - These are synthetic organic chemicals that vaporize at relatively low temperatures.