In order to investigate possible relationships between exposures to water contaminants and the development of birth defects in the Rathbun Lake area, water samples were collected and analyzed and the results linked to incidence rates of adverse health outcomes by community. The University Hygienic Laboratory collected and analyzed water samples from Rathbun Lake, from the Rathbun Regional Water Association water treatment plant, and from various points along the water distribution system to assess the seasonal fluctuation of herbicides, nutrients, and total coliforms. A database containing the results was developed and utilized by CHEEC researchers to continue assessment of factors affecting LBW and IUGR in communities served by the Rathbun Regional Water Association.