The occurrence of metals, such as lead and copper, in household drinking supplies can often be a result of the corrosion of pipes and joints in water distribution systems. One measure of the potential for water to cause corrosion is the Langelier Saturation Index (LSI) (Langelier, 1936). The LSI is a measure of the potential for water to deposit a mineral layer (scale) within a water distribution system that can inhibit the corrosion of pipes and joints. Negative values of LSI suggest mineral deposition is not likely to occur while positive values indicate conditions favorable to mineral deposition. Negative values of LSI might be indicative of conditions that lead to elevated concentrations of metals, such as lead and cooper, in household water.