Nova Scotia Surface Drinking Water Supply Characterization
Within Nova Scotia, approximately half of the drinking water comes from groundwater sources and half from surface water sources. In general the surface water in Nova Scotia is of good quality, with very little agricultural, industrial, wildlife and human threats upstream of drinking water sources.
Health Canada has published an updated protozoa guideline that recommends that treatment for surface water and groundwater under the direct influence (GUDI) sources be based on 3-log reduction for Cryptosporidium and Giardia unless source water quality requires a higher log reduction. The current Nova Scotia treatment standards do not reference Cryptosporidium and do not take into account higher log reductions for more contaminated sources. Reduction credits are assigned for different aspects of a treatment system. Similarly to Giardia reduction requirements, many jurisdictions are adopting a minimum requirement of 3.0-log reduction for Cryptosporidium.
The Centre for Water Resources Studies (CWRS), at Dalhousie University is working with Nova Scotia Environment to characterize the quality of surface drinking water supplies in Nova Scotia in order to provide non-biased science based evidence that can help to inform policy decisions.