Largely because of their low cost, earthen manure storages are the choice of most Manitoba hog producers but currently there are few case studies documenting the effects of these storages on underlying groundwater supplies. This project involves study of six established storages in three distinct geological settings in southern Manitoba. The field component of the study included removing continuous sample cores from the bases of the structures and documenting local geology and groundwater condition. The laboratory component included geological classification of the sample cores and determining the concentration of contamination within the cores by determining the movement of chloride ions in seepage through the soil under the respective storages. Mathematical modeling was carried out so contaminant seepage could be predicted in the future. Contrary to what would be expected based on the usual hydraulic conductivity levels for Manitoba clay and till, the study showed contaminants from the storages moved deeper in clay than in till. These results suggest that fractures in the clay units examined acted as conduits for fluid flow, a factor that should be considered when developing design criteria for these kinds of storages.