If your tap water has suddenly started smelling earthy or musty, you are not the only one. Metro Atlanta water systems are again dealing with seasonal compounds from Lake Lanier that can affect taste and smell even when the water remains safe to drink.
The Atlanta Journal-Constitution reports that the compounds are 2-methylisoborneol, known as MIB, and geosmin. They are associated with algae and tend to become more noticeable in late summer and early fall.
The smell can be noticeable at very low levels
Forsyth County reported a raw-water MIB concentration of 213 parts per trillion in a September 1 sample. Treatment reduced that level to 22.3 parts per trillion before distribution, according to the AJC.
People can begin noticing MIB in drinking water at around 10 parts per trillion, which helps explain why the water can taste or smell different even after treatment significantly lowers the concentration.
Forsyth officials told customers the water is safe to use and drink. Some treatment approaches can also make chlorine taste or smell more noticeable while utilities work to manage the seasonal issue.
Utilities are looking at longer-term fixes
The problem has appeared around this time in previous years. Cobb County-Marietta Water Authority has allocated money to evaluate advanced treatment methods intended to improve taste and odor control.
For residents, the key distinction is between an unpleasant taste or smell and a safety warning. Utilities have not issued a boil-water advisory tied to this Lake Lanier taste-and-odor issue.
