EnvGloss/H/Hardness

Importance

 * Calcium and magnesium compounds can precipate out of water to form deposits in sinks, pipes, etc. This can be of importance for boilers, water supply systems, and home pipes.
 * Calcium and magnesium ions bind with soap and detergent reducing their effectiveness.

Standards

 * Typical values - &sim;0 to >500 mg/L
 * There is no international standard on hardness. Hard water is general considered to be over &sim;100 mg/L (different organizations used slightly different definitions).

Links
Wilkes University Center for Environmental Quality