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Earthy taste and odor to tap water is harmless and temporary

This issue is common to our region

Post Date:09/01/2017 5:19 PM

Over the next few weeks, some residents may perceive an “earthy” taste and odor in the city’s tap water. If this occurs, it’s not your imagination – and you can rest assured that your drinking water is safe. This issue is common to our region.

The musty smell and taste come from compounds produced by certain algae, particularly blue-green algae, which are prevalent in warm regions with deep storage reservoirs, or lakes. While these algae byproducts can affect the smell and taste of drinking water (even at very low levels), they have no adverse health effects.

Tempe uses powder activated carbon (PAC) to absorb these compounds and alleviate the musty taste and smell. At certain times of year, the smell may be noticeable – even with the use of PAC – due to elevated levels of algal byproducts in our source waters. This typically occurs in the late summer and fall when algae die off due to cooler temperatures and release more odor-causing compounds. Tempe has ongoing partnerships with Arizona State University and Salt River Project to monitor and treat algal growth in the lakes and canals to minimize these occurrences.

While you may at times experience an earthy smell and taste, your water continues to be safe to drink. During these occurrences, running water through a refrigerator filter or a carbon filtration pitcher can improve taste. Chilling drinking water and adding lemon slices can also help.

For more information about your water, visit If you have any questions, call Tempe 311 at 480-350-4311.


Nikki Ripley
City of Tempe

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