Impacts of Sewers on Groundwater Quality

This paper summarizes the findings of a recent research project on groundwater contamination from leaking sewers, which was completed for the Construction Industry Research and Information Association. Fifty-four incidents were identified in England and Wales from a combined questionnaire survey and literature review. In addition to recorded incidents, the poor quality of many urban groundwaters suggests some effects from leaking sewers. Age is considered to be the most significant characteristic governing leakage from sewers; ground conditions (predominantly aquifer vulnerability) and usage (private versus public ownership) are also important factors relating to the likelihood of groundwater pollution from leaking sewers. Recommended strategies for reducing groundwater contamination include (a) modification of existing criteria for the service performance grading of existing sewers, (b) improved construction of new sewers in appropriate areas, (c) increased groundwater monitoring, and (d) risk assessments for new groundwater sources.