Glossary

Learn about the different types of contaminants that might put your family at risk.

indicator
A material which can be used to show the endpoint of a chemical reaction, usually by a color change, or a chemical concentration by a depth or shade of color.
influent
The stream entering a unit or process, such as the hard water entering an ion exchange water softener, or turbid water entering a filter system.
inorganic matter
Substances not derived from living organisms and containing no organically produced carbon; includes rocks, minerals, and metals.
installation
The process of connecting conditioning equipment into the water system and a drain line provided where necessary.  The term is also used to refer to the complete assembly of piping, valves, drain line, water conditioning unit, and related equipment.
intermittent flow
The term usually applied to the interrupted patterns of water usage; also used in reference to specific on-off flow patterns selected to test the performance of water conditioning equipment under standard conditions which may or may not be similar to actual patterns of use. 
ion
An atom, or group of atoms which function as a unit, and have a positive or negative electrical charge due to the gain or loss of one or more electrons.
ionization
The process in which atoms gain or lose electrons and thus become ions with positive or negative charges; sometimes used synonymously with dissociation; the separation of molecules into charged ions in solution. 
iron
An element (Fe) often found dissolved in ground water (in the form of ferrous iron) in concentrations usually ranging from zero to 10 ppm (mg/L).  It is objectionable in water supplies because of the staining caused after oxidation and precipitation (as ferric hydroxide), because of tastes, and because of unsightly colors produced when iron reacts with tannins in beverages such as coffee and tea.
iron bacteria
Organisms which are capable of utilizing ferrous iron, either from the water or from steel pipe, in their metabolism and precipitating ferric hydroxide in their sheaths and gelatinous deposits.  These organisms tend to collect in pipe lines and tanks during periods of low flow and to break loose in slugs of turbid water to create staining, taste, and odor problems.