Total Hardness

Abstract

Some waters do not produce appreciable lather with soap when used for washing hands or bathing. When such waters are boiled, a scaly residue may be left in the container. These waters are called hard waters, and the failure to produce copious lather results from precipitation of the soap by minerals in the water, and the scale in the container is caused by precipitation of carbonates. Because the hardness of water effects the use of water for domestic and industrial purposes, there has been a tremendous interest in this water quality property for a long time. Thus, it is important for those involved in considerations of water quality and water supply to have a clear understanding of total hardness.