Corrosivity, Alkalinity, pH, Calcium, Conductivity, and Temperature
Alkalinity, pH, calcium, conductivity (a measure of dissolved minerals), and temperature contribute to the tendency of water to be corrosive or scaling.
Corrosive water will attack plumbing components and can leach metals such as copper and lead. At elevated temperatures, as with hot water plumbing, corrosivity will increase.
Scaling water leaves mineral deposits which can result in a reduction in pipe capacities and pressures. A proper balance of these characteristics is optimal and results in a light coating of calcium carbonate on plumbing surfaces which protects against corrosion but does not build up scale.
Artesian well water typically has a pH greater than 7 (basic), while surface water or shallow well water typically has a pH less than 7 (acidic). A pH value between 6.5 and 8.5 is preferable.