Water, while one of the most critical ingredients in living organisms, also is one of the most complicated mixtures of chemical substances known. It is not that the chemistry of the compound known as water is so complicated, but rather the contaminants in it make it variable and difficult to handle. A water analysis is really a compilation of the types and quantities of water contaminants.

Article appeared in the Practical Guide to Water Treatment, which was included with the vol. 41, no. 5, May 1999 issue.