The Impact of Local Climate Change on Drinking Water Quality in a Distribution System

In this study, air temperatures were collected between 1985 and 2016 and compared to water temperatures in four locations in the distribution system of Pasadena Water & Power (PWP) that received imported surface water between 2001 and 2016 and from the purveyor of imported water. The concentration of chloramine residual and nitrite concentrations were collected between 2001 and 2016 these five locations. The results indicate that the median nighttime temperature of the period 2009 - 2016 was 1.6 ^oC warmer than the period of 1985 - 2000 and 0.5 ^oC warmer than the period 2001 - 2008. The median water temperature in the four distribution system samples increased by 0.8 ^oC to 1.4 ^oC depending on the location over the study period (p<0.001). The median chloramine concentration fell significantly (p<0.001) at three distribution system locations and the nitrite concentrations increased significantly at all four distribution system locations.