An official website of the United States government.

Due to a lapse in appropriations, EPA websites will not be regularly updated. In the event of an environmental emergency imminently threatening the safety of human life or where necessary to protect certain property, the EPA website will be updated with appropriate information. Please note that all information on the EPA website may not be up to date, and transactions and inquiries submitted to the EPA website may not be processed or responded to until appropriations are enacted.

We've made some changes to If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Chapter One of the SW-846 Compendium: Project Quality Assurance and Quality Control

The goal of this chapter is to provide an understanding of environmental data and the need for quality. EPA has developed numerous guidance documents on quality assurance. This chapter is not intended to summarize EPA guidance. Instead, this chapter will provide familiarity with regulations and guidance relating to quality assurance and where to find them.

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.