The topic of “architectural water testing” creates a lot of confusion amongst architects. This is because many architects who have worked on small to midsize commercial projects have likely never encountered it. However, architectural testing seems to be growing on larger commercial projects, even though it comes at an additional upfront cost for the owner. This upfront cost is validated by potentially preventing costly errors once the constructed building is furnished and occupied. The objective of water testing during new construction is to mitigate water intrusion by catching any product compatibility, field installation or documentation errors where two wall systems transition/ interface. ASTM E1105 is one of the most popular field water tests as it simulates a heavy wind driven rain.