Frequent Questions

Are drinking water analytical methods approved by EPA as part of the Alternate Test Procedure (ATP) Program available for use in all states?

State adoption of alternative methods approved under the expedited process is optional. States may choose to allow only a more limited set of methods to be used for compliance. States that choose to allow the alternative methods approved through this expedited process will be consistent with the requirement that states must have programs at least as stringent as the federal drinking water program in order to have primary enforcement responsibility for the drinking water program.

EPA compiles a list of the alternate test methods that have been approved for analyses in 40 CFR Part 141, Subpart C, Appendix A. This list and additional information about the expedited approval process is available at Parties interested in determining whether a state has adopted the methods approved as part of the ATP Program should contact the state drinking water office directly. Contact information for state drinking water offices is available at
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