The following pages present the background, procedures and outcome of an aquifer vulnerability assessment conducted for Hornby Island using the DRASTIC aquifer vulnerability model with arcGIS. Model inputs were derived from data provided by several agencies, Islands Trust, Natural Resource Canada, Ministry of Water Land and Air Protection and Regional District of Comox Strathcona. The rankings of inputs were determined using two previous assessments, one of which was conducted in Australia and the other for the Southern Gulf Islands. As an added dimension, the Hornby Island aquifer vulnerability assessment compared between two different precipitation levels, the dry months and the wet months. The outcome demonstrated spatial variability in aquifer vulnerability, as well as increased aquifer vulnerability during the wet months assessment. The results are limited by the questionable variability in depth to water table data and the exclusion of fractures that are present in the island geology.