As previously reported, customers served by WSSC Water’s Potomac Water Filtration Plant (Potomac River) may still notice changes in the taste and odor of their tap water because of algal activity in the Potomac River (map available below). This change is not harmful and is due to an increase in a naturally occurring substance, Geosmin, caused by warmer weather and low water levels in the Potomac River. As Geosmin are prone to fluctuate with rain and changing water levels, customers may notice order is stronger at certain times than others. This is completely normal.
The odors from the naturally occurring compound, Geosmin, are not toxic. Because the human nose can detect Geosmin concentrations at very low levels, the unpleasant smell can cause sensitive individuals to experience nausea/headaches. Despite the taste and odor issues, the water remains safe, meeting all EPA Safe Drinking Water Act standards.