It may not smell or taste terrific, but that big gulp of water is as safe as ever

If you’ve noticed a “musty” taste and odor in your tap water recently, it’s not your imagination – and you can rest assured that your drinking water is safe. The city of Tempe on Aug. 18 changed the way it treats surface water for taste and odor in order to effectively treat an influx of mud and particulates caused by recent stormwater runoff in the Sunflower Fire burn area.

The fire burned more than 16,000 acres in the Tonto National Forest northeast of the Valley – mostly within the upper drainage area of Sycamore Creek. Runoff from the creek enters the Verde River and eventually the Salt River Project canal system that supplies water to Tempe’s two water treatment plants.

In anticipation of muddy storm runoff in the water Tempe receives at its treatment plants, the city temporarily suspended use of powder activated carbon, which it normally uses to treat the compounds that cause a musty or earthy odor in drinking water.

The musty smell and taste come from compounds produced by certain algae. Tempe typically uses powder activated carbon to absorb these compounds and alleviate the taste and odor issues. While algae byproducts can impact the smell and taste of drinking water, they have no adverse health effects. Tempe’s drinking water continues to meet all Safe Drinking Water Act requirements and is absolutely safe to drink.

Intense storms last week in the area of the Sunflower Fire resulted in runoff that contains high concentrations of mud and particulates draining into the Verde River and Salt River Project canal system. That system supplies water to Tempe’s treatment plants. Suspending the use of powder activated carbon allows the city to effectively treat water containing muddy storm runoff.

Due to forecasted storms on the watershed throughout the week, Tempe anticipates that its suspension of powder activated carbon will continue through the week and possibly into next weekend. Tempe’s drinking water continues to be safe, and residents should notice reduced “earthy” smell and taste any day now, if not already. In the meantime, running water through a refrigerator filter or a carbon filtration pitcher, such as a Britta, can improve taste. Chilling drinking water and adding lemon slices can also suppress musty taste and odor.

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