Its smell and taste took a suspicious "musty" change, but Tempe's drinking water is safe, officials say.

Tempe on Saturday changed the way it treats surface water to combat mud and particulates in recent storm-water runoff in the Sunflower Fire burn area, where more than 16,000 acres were blackened in May. The storm water ran into Salt River Project's canal system that feeds Tempe's treatment plants.

The city temporarily stopped using powder-activated carbon, which treats compounds produced by algae that cause the earthy odor, because the method used to treat mud and particulates makes the carbon ineffective, Tempe public-works spokeswoman Amanda Nelson says.

Though algae products can affect taste and smell, they have no adverse health effects and Tempe's water still meets all Safe Drinking Water Act requirements, Nelson says.

Using filters or chilling the water and adding lemon slices can help improve taste until the water returns to normal next week.