Raw waters with high TOC content present unique challenges to municipal treatment plant operators. These problems are exacerbated when the raw water is very cold. Plants in the Pacific Northwest are being subjected to raw water with increasing TOC content and regulations requiring lower disinfection byproducts. This presentation will discuss issues related to optimizing membrane plant operations with cold raw waters that contain high TOC levels. Environmental trends, regulatory trends, and operational challenges will be presented along with best practices to optimize treated water quality.