The Mass Balance Sampling Network consists of surface water sampling stations and groundwater monitoring wells to measure flow and major ionic concentrations near the White Lodge #5 Wellfield of the Dedham-Westwood Water District in eastern Massachusetts. Meteorological observations, as well as local and state deicing agent application rates complement the Network, which will include monthly and logged data from October 2006 through June 2011. A preliminary analysis of first year groundwater hydraulic data suggests that the Fowl Meadow Aquifer is confined within 330 m of Well #5, with equivalent, site averaged transmissivity of 0.0061 m2/s and storativity of 0.00012.