Protecting drinking source water quality is a critical step in ensuring a safe supply of
drinking water. Increasingly, drinking source water protection programs rely on the active
participation of various stakeholders with differing degrees of water science knowledge.
A drinking source water quality index presents a potential communication and analysis
tool to facilitate cooperation between diverse interest groups as well as represent
composite water quality. We tested the effectiveness of the Canadian Council of Ministers
of the Environment Water Quality Index (CCME WQI) in capturing expert assessments of
drinking water quality. In cooperation with a panel of drinking water quality experts we
identified a core set of parameters to reflect common source water concerns. Drinking
source water target values were drafted for use in the index corresponding to two basic
treatment levels. Index scores calculated using the core parameter set and associated
source water target values were strongly correlated with expert assessments of water
quality. We recommend a modified index calculation procedure to accommodate parameters
measured at different frequencies within any particular study period. The resulting
drinking source water CCME WQI provides a valuable means of monitoring, communicating,
and understanding surface source water quality.