|Abstract:||The Illinois State Water Survey (ISWS) quality system consists of several components that together document the management practices used to ensure the quality and reliability of environmental data collected or developed at this scientific institution. The ISWS Quality Management Plan (QMP), the key component of the system, is the “umbrella” quality assurance document that describes the processes and procedures for staff and management to follow in the collection and reporting of environmental data. It is patterned after a national consensus standard, ANSI/ASQC E4-1994, and a United States Environmental Protection Agency (USEPA) guidance document developed to assist agency contractors in developing their own agency-specific QMPs. The USEPA requires all contractors producing environmental data for use by the Agency to develop QMPs that follow these guidelines. This QMP is intended to meet the requirements of the ISWS, USEPA, and other funding agencies that support environmental data collection and reporting activities at the ISWS.