Effective communication and coordination are critical when investigating a possible drinking water contamination incident. A contamination warning system is designed to detect water contamination by initiating a coordinated, effective response to mitigate significant public health and economic consequences. This article describes historical communication barriers during water contamination incidents and discusses how these barriers were overcome through the public health surveillance component of the Cincinnati Drinking Water Contamination Warning System, referred to as the "Cincinnati Pilot." By enhancing partnerships in the public health surveillance component of the Cincinnati Pilot, information silos that existed in each organization were replaced with interagency information depots that facilitated effective decision making.