The Cape Cod National Seashore (CCNS) collects data on water quality and quantity in near real time to assess environmental impact and change at representative locations throughout the park. Water level has been a key parameter measured since 2005 for tracking system responses to the projected restoration of tidal exchange. Water level data collected from our sites to date had not included any compensation for changes in barometric pressure during deployments. It was essential to gain the most accurate water level data set that we could to make the best management decisions possible. In May 2009 a workshop was held at the ARC to introduce a new calibration procedure for non-vented instruments, as a first step in achieving this higher level of accuracy.