Prior to being treated, the City’s water flows through creeks and ditches and is stored in reservoirs. These features function as a home to fish, wildlife, and aquatic vegetation. As water levels and temperatures vary over the course of the year, those ecosystems change.
In the spring, reservoirs fill with cold mountain snowmelt that has minimal plant material, but may be high in minerals picked up as runoff flows rapidly through creeks and ditches. During the spring and fall, temperature changes can cause reservoirs to “turn over” with cooler water sinking to the bottom and warmer water rising to the top. During the warm summer months, algae blooms can develop and then die off. In the fall, vegetation in and around the reservoir may die off or go dormant. In the fall leaves enter the reservoir and begin to decompose. During late summer and into winter, reservoir levels are drawn down as customer demands exceed stream flows. Each of these seasonal changes has impacts on the characteristics of the water that is delivered to the City’s water treatment facility.
The water treatment process filters out harmful materials and includes a disinfection process to prevent bacteria and organic materials from growing once water leaves the plant. Activated carbon is also used to help reduce any residual taste and odor. Even with treatment, there are subtle changes in water chemistry that can be detected by the human palette. Some people may also notice the process adjustments that are made to address source water variations, such as slight variations in chlorine levels.
Storing drinking water in the refrigerator can help reduce the variability of taste and odors due to changes in the City’s source water. Colder water releases less water vapor in to the air which impacts perceptions of variation in smell and taste. Storing water in the refrigerator also allows residual chlorine to dissipate. Running water until it turns cold before filling a pitcher will help flush out building plumbing and bring in fresh water from the City system.