Proceedings available at: http://www.extension.org/67603 Agricultural filter strips are commonly used to treat runoff from agricultural farmstead areas. Many filter strips have been assessed in terms of surface water quality impacts but have failed to determine the fate of pollutants once they have infiltrated the soil subsurface. Two side-by-side filter strips plots were installed to assess the performance of and determine the fate of contaminants in a filter strip system. One of the two plots also contained a pretreatment system to facilitate nitrogen removal in an attempt to reduce nitrate leaching. Both plots were lined with an impermeable membrane to collect subsurface leachate as well as surface runoff. A mass balance could then be determined for these filter strip systems to assess the fate of nutrients and the ability of a low cost pretreatment system to reduce nitrate leaching.