(a) These methods cover the determination of acidity and basicity (alkalinity) in industrial water and industrial waste water. Procedures are given for the determination of a titration curve that will define the inflection points and the buffering capacity, and for the determination of acidity or basicity (alkalinity) to a predesignated pH end point. Three methods are given, as follows: Sections Referee Method (Electrometric Titration) 5 to 13, Non-Referee Method A (Color-Comparison Titration) 14 to 21, Non-Referee Method B (Color-Change Titration) 22 to 29. (b) The Referee Method is electrometric and is the most precise and accurate of the three methods. Non-Referee Method A depends on the matching of colors with those of buffered standards and is satisfactory for routine control use, provided the sample contains no buffering materials at the end point. Non-Referee Method B depends upon the color change of an indicator during the course of a titration and is suitable for routine use, providing the sample contains no buffering materials at the end point.