In March 2013, the U.S. Environmental Protection Agency released a document written for utilities developing a sampling and analysis program as part of a Contaminant Warning System but that may also be useful to utility partners such as public health, state, EPA regional, and commercial laboratories. The document provides an overview of the role of sampling and analysis in a CWS, provides a framework for building laboratory capabilities for response to water contamination, presents contaminant classes of concern to water security, lists methods for a representative number of contaminants from those classes and provides information on the role of national laboratory networks in responding to drinking water contamination events.