Weather-Related Changes in Tap Water Taste Are Temporary
By Traci Peterson, Arlington Water Utilities
Posted on January 14, 2021, January 14, 2021


Some residents may have noticed a change in the taste of Arlington tap water following the latest cold snap. Unfortunately, testing at the City’s Pierce-Burch Water Treatment Plant, which uses water pumped from Lake Arlington, is showing that levels of the naturally occurring chemical compound geosmin have increased recently (as they have at times during past winters). Geosmin is not a harmful compound. However, it can give water a musty or soil-like taste and odor.

Arlington water treatment staff will continue to monitor the geosmin levels and address taste and odor issues as much as possible during the treatment process. Recent results show that water treatment processes are eliminating more than 95 percent of geosmin in water coming from Lake Arlington before it is sent to residents, resulting in tap water with less than 50 parts per trillion. Geosmin can be detected by some individuals at levels down to 5 parts per trillion. As an example of how low a level that is, 5 parts per trillion equals about 1¼ cups of geosmin diluted into the entire volume of Lake Arlington.

Geosmin is produced by algae found in surface water. Extreme temperatures can kill off algae in surface water, which releases the geosmin into the water. The EPA – which sets acceptable levels for any compounds that could harm human health or cause significant aesthetic issues – does not include geosmin in the category of compounds requiring monitoring. Heating the water increases the volatility of compounds like geosmin, which explains why the smell is more easily detected when you are in the shower or when water is used for hot beverages. To make the water taste better, try chilling it, adding ice cubes, a slice of lemon, or a few drops of lemon juice. And remember, that the change in taste and odor is only temporary.

Click here to visit the City of Arlington website’s Water Department page, which features a list of common water quality questions.

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