ABSTRACT
Note: This chapter uses the term ‘‘must’’ to refer to certification criteria that are required by the National Primary Drinking Water Regulations which include the approved drinking water methods. The term ‘‘should’’ is used for procedures that, while not specifically required by the regulations, are considered good laboratory practice for quality assurance. To assure the validity of the data, it is critical that laboratories observe both the regulatory and nonregulatory criteria. Certification Officers have the prerogative to refuse certification if the quality control data are judged unsatisfactory or insufficient.
