Nitrate is a necessary nutrient for crops, but high nitrate concentrations in water can negatively affect aquatic ecosystem and human health. At AAFC-AAC Harrington Research Farm (PEI), 3D cross-hole electrical resistivity imaging (ERI) is being used to investigate the transport of conductive tracer through a vadose zone as a proxy for the transport of nitrate under natural recharge conditions. The objectives are to investigate the effect of heterogeneity on transport pathways and infer how long it would take changes in farming practices at the surface to affect nitrate loading to the underlying aquifer. Borehole geological logs, and pre-tracer resistivity surveys indicate the 17 m deep vadose zone can be divided into five layers including ~ 6 m of soil and glacial till overlying interbedded sandstone and shaley sandstone. On March 27th, 2015, 1.1 m of snow was removed from a 15.2 m2 area positioned symmetrically inside the triangular cross-hole resistivity array and 100 kg of granular KCl was evenly distributed on the ground surface. The removed snow was replaced to await the spring thaw. Post-tracer surveys indicate tracer had percolated to depths of 1 m, 1.2 m, 3.0 m and 3.5 m by the 4th, 26th, 30th, and 46th days after tracer application. Its movement slowed significantly by early May with the end of snow melt. The most recent data from February 4th, 2016 yielded a resistivity model very similar to that obtained in mid-May, 2015. The stalling of tracer is thought to be caused by a low permeability layer. Preferential percolation of tracer towards west was observed, indicating heterogeneity within overburden. Tracer movement will be monitored through the spring thaw of 2016, and results will be used to improve infiltration and percolation models. Forward modelling and volume of investigation studies are ongoing to determine the sensitivity and resolution of this ERI array.