The Iowa Department of Natural Resources (IDNR) certifies environmental laboratories throughout the United States for the Clean Water Act (CWA)[wastewater (WW)], drinking water (SDWA), solid waste or contaminated sites (SW/CS) and underground storage tank (UST) environmental programs. The objective of the environmental laboratory certification program is to ensure that the results of testing performed are accurate and legally defensible. Laboratories reporting data to the IDNR for these programs must be certified by the IDNR. The IDNR Water Supply Section administers the certification process. The University of Iowa Hygienic Laboratory (UHL) provides technical support as the laboratory appraisal authority.