Temporary Water Discoloration Linked to Seasonal Conditions

The City of Bloomington Utilities (CBU) has received an increase in reports from customers noticing  discolored water and a more frequent need for replacement of water filters.

The change is related to seasonal conditions in Monroe Reservoir and adjustments CBU is making at the water treatment plant to maintain effective treatment and manage disinfection byproducts (DBPs). As reservoir conditions change, CBU can draw water from different depths of the lake. Current conditions have required drawing from a lower level, where naturally occurring manganese is more prevalent. 

Manganese is a naturally occurring mineral that can produce a temporary brown or yellow tint to the water or increase shortened replacement cycle for household filters. While manganese can affect water appearance and taste, it does not pose a health risk at the levels currently being observed and is not regulated as a primary contaminant by the U.S. Environmental Protection Agency (EPA). All samples taken today throughout the distribution system are  within all applicable EPA health advisory levels.

CBU regularly monitors source and finished water quality and adjusts treatment processes as reservoir conditions change. The water treatment plant has limited capacity to fully remove manganese at the current source-water levels. To help mitigate the issue, CBU is conducting additional hydrant flushing and enhanced monitoring throughout the water system to help improve water clarity and ensure the continued safety of our drinking water. 

For residents seeing discoloration, CBU recommends running cold water through a faucet for several minutes to help clear any discolored water from household plumbing and changing water filters more frequently until conditions normalize. If the discoloration continues after flushing, Customers can email [email protected] with their name and address. This information helps CBU identify affected areas and coordinate additional hydrant flushing where appropriate.