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Osceola Water Works has confirmed that West Lake, the source of Osceola’s drinking water, recently experienced a natural process known as lake turnover. This seasonal event can temporarily affect the taste and odor of drinking water, even though the water remains safe to consume.
Lake turnover is the process of a lake’s water mixing from top to bottom. It happens naturally, most often in the fall and spring, when air temperatures fluctuate. During summer, lake water forms a top layer that is warm and heated by the sun and a bottom layer that is colder, darker, and denser.
As temperatures cool during the transition from summer to winter, surface water becomes heavier and sinks. This sinking water pushes the deeper water toward the top, causing the lake to literally “turn over.”When this happens, decaying organic material, algae, and naturally occurring gases that have settled at the bottom of the lake can be stirred into the water column.
There are several factors that are making this turnover more noticeable to Osceola Water Works customers:
- Recent temperature fluctuations, along with subsequent freezing and thawing has increased the frequency of lake turnovers that are occurring this winter season.
- When water levels were low during the recent drought, excessive vegetation grew along exposed lake areas. When lake levels recovered, the vegetation remained beneath the water and slowly began to decompose.
- The decomposing vegetation has contributed to an unexpected increase in Geosmin and MIB. Geosmin and MIB are naturally occurring organic compounds that cause earthy, musty tastes and odors in drinking water. They are notoriously difficult to remove with conventional water treatment processes, but pose no health risk and create significant taste/odor challenges.
- A very small concentration of 5 to 15 parts per trillion of geosmin can create noticeable tastes or odors.
Although your drinking water is safe to consume, Water Works knows that customers expect their water to taste good and be odorless. All water treated by the Osceola Water Works receives complete treatment in accordance with state and federal regulations and meets the Primary Drinking Water Standards, as established by the EPA.
OWW staff has already undertaken steps to counteract the effects of turnover.
“We’ve slowed the plant as much as we can to allow more contact time with the carbon filtration system to remove organic material, and we’re cleaning the filters more frequently to improve effectiveness,” said Cory Gallup, Water Plant Foreman for Osceola Water Works. “Recent rain should help dilute the concentration of geosmin, but we’ve also increased our testing frequency and are keeping a close watch on the odor levels.”
Beyond adjusting pumping methods to limit impacts from the lake, OWW will consider flushing water lines throughout the system to push cleaner, treated water through and using additional treatment processes where appropriate.
Placing tap water in a covered pitcher in the refrigerator or adding lemon juice to your drinking water can significantly reduce taste and odor problems for the short term. These conditions typically improve as lake temperatures equalize and stabilize. Once the lake fully settles after turnover, the taste and odor of tap water should return to normal.
Osceola Water Works appreciates your patience and assures customers that staff are doing everything possible to restore normal taste and odor while continuing to provide safe, reliable drinking water.