AWWA WQTC63996

Understanding source water quality in terms of its variability is paramount in drinking water applications. In this paper, spatial and temporal trends of total organic carbon (TOC) for surface water plants in the continental United States (US) are examined. Using average TOC values from the US Environmental Protection Agency's Information Collection Rule database, a local polynomial method was used to estimate average TOC concentrations at several locations and contoured to understand the associated spatial variability. The highest TOC values were seen in the central US and Florida. The lowest values were seen in the Pacific Northwest. Significant variability in the temporal trends was observed across the US. Time series plots show that regionally there is a rich variety in monthly TOC values, and that seasonality should be considered. Includes 6 references, table, figures.