Lake Houston is a surface-water-supply reservoir and an important recreational resource for the city of Houston, Texas. Growing concerns over water quality in Lake Houston prompted a detailed assessment of water quality in the reser-voir. The assessment focused on water-quality constituents that affect the aesthetic quality of drinking water. The hydro-logic and water-quality conditions influencing the occur-rence of taste-and-odor causing organisms and compounds in Lake Houston were assessed using discrete and continuously monitored water-quality data collected during April 2006-September 2008.