The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the nation's air, water, and land resources. Under a mandate of national environmental laws, the Agency strives to formulate and implement actions leading to a compatible balance between human activities and the ability of natural systems to support and nurture life. To meet this mandate, the EPA's Office of Research and Development provides data and science support that can be used to solve environmental problems and to build the scientific knowledge base needed to manage our ecological resources wisely, to understand how pollutants affect our health, and to prevent or reduce environmental risks. The Environmental Technology Verification (ETV) Program has been established by the EPA to verify the performance characteristics of innovative environmental technology across all media and to report this objective information to permitters, buyers, and users of the technology, thus accelerating the entrance of new environmental technologies into the marketplace. Verification organizations oversee and report verification activities based on testing and quality assurance protocols developed with input from major stakeholders and customer groups associated with the technology area. ETV consists of six verification centers. Effective verifications of monitoring technologies are needed to assess environmental quality and to supply cost and performance data to select the most appropriate technology for that assessment. Under a cooperative agreement, Battelle has received EPA funding to plan, coordinate, and conduct such verification tests for 'Advanced Monitoring Systems for Air, Water, and Soil' and report the results to the community at large. Testing was conducted on five multi-parameter water monitors for distribution systems: Analytical Technology, Inc., Q45WQ Continuous Multi-Parameter Water Quality Monitor; Clarion Sensing Systems, Inc., Sentinal (TM) 500 Series Continuous Multi-Parameter Water Quality Monitor; Rosemount Analytical Model WQSContinuous Multi-Parameter Water Quality Monitor; Man-Tech Inc., TitraSip (TM) SA System Continuous Multi-Parameter Water Quality Monitor; and the Hach Company Water Distribution Monitoring Panel and the Event Monitor (TM) Trigger System.