Warm Weather Can Bring Changes to Your Water

During the summer months, Skagit PUD typically sees an increase in the number of customer calls involving taste and odor concerns. Taste and odor issues are some of the most difficult for a water system to address.

One reason for the difficulty is that taste and odor evaluations are very subjective: what is offensive to one individual may not be even detectible to another.

All water has its own unique taste and odor characteristics. Skagit PUD’s water treatment plant draws water from Judy Reservoir, east of Clear Lake, which is supplied from four streams within the Cultus Mountains and the Skagit River. Like many other water systems, we occasionally experience taste and odor changes.

An earthy or musty smell, particularly in hot water, may be the result of an algal bloom in the untreated water supply. Algae thrive at different times of the year in reservoirs. Taste and odor producing algae typically bloom in the late summer or fall. Although algae are removed during the treatment process, some of their metabolites (organic compounds) may be left behind.

The two most common metabolites are geosmin and 2-methylisoborneal (MIB). Even though these compounds are harmless, the human senses of taste and smell are extremely sensitive to them and can detect them in the water at concentrations as low as five parts per trillion.

Algae are common, normal inhabitants of surface waters and are beneficial to the health of a water body. Low concentrations of most algae are an asset rather than a liability in a raw water source. Algae are important as primary producers of organic matter at the base of the food chain and are useful indicators of pollution. They help remove excess nutrients, produce oxygen and provide spawning habitat for fish.

Fortunately, for PUD customers, these earthy or musty odor events are temporary in nature, usually disappearing entirely when the temperature of Judy Reservoir changes. The byproduct that causes the odor is not harmful, nor will it affect normal water usage.

Skagit PUD customers can take some measures to reduce the taste and odor in the drinking water. Customers can refrigerate the water in an open container to help the odor evaporate, add ice cubes as cold water tastes better than warm water, or add a few drops of lemon juice to the water. Home treatment devices that use granular-activated carbon are also effective in reducing these taste/odor compounds.

Please feel free to contact us at (360) 424-7104, if you have questions about the quality of your water.