Nitrate compounds in ground water frequently may be attributed to pollution from surface sources such as septic tanks or livestock areas. Because of this situation, sanitary seals in water wells used for domestic purposes are mandatory. The amount of total dissolved solids in water indicates the total mineralization of the water. Water containing an excessive amount of total dissolved solids may also be expected to exhibit other water quality hazards, usually excess chloride ion. Areas of excessive total dissoved solids are shown on Figure 22.
Carbonate hardness becomes apparent after water has been heated.
Heating reconstitutes the soluble calcium and magnesium bicarbonates into precipitates of insoluble carbonates. The precipitates adhere to heated surfaces, such as the inside of water heaters and hot water pipes, and ultimately cause a reduction in the capacity of the fixture. Noncarbonate hardness is not affected by heat, as it is principally caused by the presence of calcium sulfate. Both forms of hardness reduce the cleansing ability of many soaps and detergents. Water softening is a process for the removal of the hardness-forming mineral constituents in water.