It's a question we hear from Westminster residents each year. Over the next couple of weeks into mid-October, you may notice that your water tastes a little different. Don’t worry—that’s normal! Each fall around early October, the turnover process begins at Standley Lake, which is a seasonal change between summer and winter when water from the bottom of the lake naturally rises to the top. Turnover helps supply the lake’s ecosystem with vital nutrients and oxygen. It may potentially cause our drinking water to smell or taste a little earthy, but it’s still perfectly safe to drink.

What is turnover and why does this happen?

During the summer, the sun heats the water in Standley Lake and creates thermal layers in the reservoir. Warm water rises to the top while cool water sinks below. When the warmer water at the surface begins to cool off in the fall, it will sink and the layers of water will begin to mix—a process called turnover.

Is turnover normal?

Yes! It happens in many other lakes and reservoirs. This change of water temperature layers can cause water that was near the bottom to rise to the surface, potentially causing an unpleasant smell or earthy taste in the water, but the water is still safe to drink as normal.

How long will this different smell and taste last?

Thankfully, it’s temporary! The turnover process normally lasts anywhere from two to four weeks and depends on how warm the air temperature is.

Is it safe to drink?

Absolutely. Our water quality specialists monitor the lake water and the water leaving our treatment facility 24/7. This process does not change the high quality of water that reaches your tap at home.

Is the City doing anything to stop the smell during this time of year?

Our water quality specialists continuously monitor our drinking water supply. Sometimes, we are able to add an oxidation additive that bonds with the odor molecules and helps reduce the smell. This additive is safe to drink and we use a minimal amount to decrease the unpleasant odors while also preserving the natural processes of Standley Lake’s ecosystem.

For further questions or concerns, you can reach out to the City's Water Quality Hotline at 303-658-2461.

You can learn more about water turnover on the National Geographic website.