Markis Fisher Introduction:Water hardness is a widespread water quality which contains dissolved compounds of calcium and magnesium and, at times, other divalent and trivalent metallic elements, according to the Water Quality Association. In addition to water, hardness is basically the measure of Mg2+ and Ca2 + concentration in water. The greater the value,the harder the water. The hardness of water can lead to many important underlying problems. Hardness of water is very important, as stated before that it can lead to significant problems. These problems greatly impact commercial business and industries. Such as utility industry, beer brewing, chicken hatcheries, steel and auto plants and many more that use large amounts of natural water. The issue that water hardness causes is known as scale formation in boilers and evaporators. When the hard water is heated or volatized it leaves behind residue, like crystals. This residue is from the Ions in water which are most commonly Mg2+and Ca2+because they dissolve in water which in turn leaves behind the residue. The residue builds up in which causes pipes to narrow, metal corrosion, structural weakness, blocks jets and tubes, act as insulator which can impede heat. The result of scale formation is extraordinarily expensive as well. Water hardness can be measured several different using total dissolved solids (TDS), atomic absorption spectroscopy (AA), or divalent cation concentration. The most common and more effective way is divalent cation concentration this is because specifically measure the components that contribute to water hardness. TDS measures ions that contribute to water hardness. AA can be used but is expensive and only measures Mg2+and Ca2+. According to Harvey ethylenediaminetetraacetic acid (EDTA) is one of the best ways for measuring total water hardness. This is because it can give its 6 lone pair of electrons to metal ions. Goes well with indicators like eriochrome black T (EBT). When titration occurs EBT reacts with and only with Mg2+which forms a red color at start of solution. Thereafter EDTA is added and reacts with Ca2+(no color), once all Ca2+has been chelated EDTA reacts with magnesium indicator making MgEDTA chelate. Mg2+is removed from indicator resulting in blue color. Atomic absorption spectroscopy attains values of metals at a point in solution. This is done by using the absorption of light by free atoms in the gaseous state. Beer-Lambert law is the principle behind how it works light is proportional to the energy change of the component; the sample first aspires in the flame. Then only when the energy levels equal, the wavelength will beabsorbed. AA can only do that. So, AA can only get one value of at a time for Mg2+and Ca2+while EDTA method you get values of concentration. Also, AA must be converted to molarity.