1.1 This guide addresses the need for each laboratory engaged in the analysis of water and wastewater to develop and maintain an up-to-date written manual that clearly and completely delineates the exact steps followed in performing every test method and procedure used in the laboratory, that is, a manual of their standard operating procedures (SOPs).

1.2 This guide details the practices necessary to provide clear in-house SOPs and a mechanism whereby the normal development and evolution of an analytical test method or procedure can be controlled and properly evaluated for incorporation into the SOP used in that laboratory.

1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in the note.