Municipal water is often pH-adjusted, in order to prevent corrosion from pipes and to prevent dissolution of lead into water supplies. During water treatment pH adjustments may also be required. The pH is brought up or down through addition of basics or acids. An example of lowering the pH is the addition of hydrogen chloride, in case of a basic liquid. An example of bringing up the pH is the addition of natrium hydroxide, in case of an acidic liquid.

The pH will be converted to approximately seven to seven and a half, after addition of certain concentrations of acids or basics. The concentration of the substance and the kind of substance that is added, depend upon the necessary decrease or increase of the pH.