Throughout the year, the Portland Water Bureau’s Water Line receives calls from customers who say their tap water appears milky white or cloudy.
In the majority of cases the cloudy water is caused by harmless air bubbles, but sometimes it can indicate a water heater issue. Fortunately, determining the cause is as simple as filling up a clear glass with water and setting it on the counter.
- If the water clears from the bottom of the glass to the top, the water has air bubbles. This reaction sometimes occurs when cold water from underground mains enters warmer pipes inside your home. Since cold water holds more dissolved air than warm water, as water warms air may be released as tiny bubbles when a tap is turned on. The water is safe to drink, the discoloring is just the result of a harmless reaction.
- If the water in the glass clears from the top-down, and white or grey particles settle to the bottom, this may indicate a water heater issue. To determine the type of issue, remove some of the particles from the water and add them to a small amount of vinegar. If the particles dissolve, this indicates mineral content and your hot water heater may require maintenance. If the particles don’t dissolve, it is likely the water heater dip tube is breaking down and repair is needed.
Home Water Quality
To learn about water quality at home, visit the Water Bureau's Drinking Water Quality webpage or contact the Water Quality Line at 503-823-7525 or WBWaterLine@portlandoregon.gov (8:30 a.m. to 4:30 p.m., Monday through Friday).