High MIB Levels in Drinking Water

Information Release For Cobb County-Marietta Water Authority’s Customers Regarding High MIB Levels in Drinking Water

High levels of MIB (2-Methylisoborneol) in drinking water are not considered a public health risk, but it can cause noticeable taste and odor issues, typically described as earthy or musty. MIB, together with geosmin, are naturally occurring byproducts of certain algae and bacteria often present in lakes and reservoirs, especially during warmer months with less precipitation.

The Cobb County-Marietta Water Authority (CCMWA) provides drinking water via the Wyckoff Treatment Division located at the west side of Cobb County and the Quarles Treatment Division at the east side of Cobb County. The Wyckoff plant, whose source water comes from Lake Allatoona, is experiencing an MIB spike coming from the Lake. The lab results provided this morning by Eurofins Scientific, Inc. confirmed the MIB spike. CCMWA has taken actions immediately to control MIB. More granular activated carbon (GAC) contactors are being placed online at Wyckoff plant as of this morning (July 24, 2025). We continue to feed the maximum available powder activated carbon (PAC) dose at the source water at the Wyckoff plant. The PAC dose has been increased at the source water at the Quarles plant. More water production is shifted to Quarles plant and Wyckoff’s flow is reduced to minimize the areas affected by the MIB spike. All these measures are taken to control the taste and odor problem. There is no cause for health concern related to MIB. Your water is safe to drink.

There are actions customers can take to reduce the unpleasant taste and smell. An activated carbon filter (such as Brita, Pur) can be used to improve the water’s taste. Getting water from the refrigerator’s water dispenser or chilling the water in the refrigerator before consumption can help.

If you have any questions or concerns, please do not hesitate to contact us.

Wholesale customers of the Cobb County-Marietta Water Authority include:
• Cobb County Water System
• City of Marietta
• City of Smyrna
• Paulding County Water System
• City of Austell
• City of Woodstock
• City of Mountain Park
• Lockheed Martin Corporation
• Douglasville/Douglas County Water & Sewerage Authority