BLOOMINGTON – City of Bloomington Utilities (CBU) has lifted the precautionary Boil Water Advisory issued shortly before midnight on Sunday, September 20, for Monroe County following storm-related power outages and a temporary increase in turbidity at the Monroe Water Treatment Plant. Sampling results from throughout the distribution system have tested clear, confirming that the water is safe to consume without boiling. While tank levels improved overnight, water pressure may remain lower than normal in some areas while the distribution system continues to recover.
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At around 6 p.m. on Friday, September 18, severe weather caused power outages that disrupted operations at the Monroe Water Treatment Plant. While the plant can typically operate at 50% capacity with its existing backup generators, additional electrical issues at the intake tower prevented treatment entirely. Following restoration of power, plant staff identified failures and operational issues with several essential pieces of equipment and systems, including raw water pumps, alum pumps, the plant’s supervisory control and data acquisition (SCADA), and communications. These issues affected the plant’s ability to maintain normal treatment operations. In particular, the loss of alum affected the filters’ ability to properly form floc and remove suspended particles from the water. As a result, turbidity levels leaving the filters increased, and, combined with low water levels in the Monroe distribution tank, turbidity reached and exceeded the maximum contaminant level of 1.0 NTU.
The Indiana Department of Environmental Management (IDEM) requires public water systems to issue a precautionary Boil Water Advisory when turbidity is detected at 1 Unit or above. CBU detected a turbidity level of 1.06 NTU at the water treatment plant at approximately 5 p.m. on Saturday, Sept. 19, above the 1.0 Unit regulatory limit.
CBU staff increased water-quality monitoring and adjusted plant operations to restore normal production and treatment conditions. About one hour after the 1.06 NTU reading, turbidity readings at the plant returned below the regulatory limit at 6:00 p.m. on Saturday, September 19, and have remained below the limit since. That did not immediately end the advisory because water moves from the treatment plant through storage tanks and distribution mains before reaching customers. CBU completed required sampling throughout the system before lifting the advisory.
“Resilience is a central part of how CBU plans for the water system,” Utilities Director Katherine Zaiger said. “That means investing in the modernization and replacement of aging equipment, controls, and backup systems that allow the plant to continue operating or recover more quickly when conditions are disrupted. Upcoming capital projects at the Monroe Water Treatment Plant, funded through our most recent rate adjustments, are designed with that purpose in mind.”
CBU has several previously approved water-system investments underway or in development. In September, CBU received a $2.375 million U.S. Environmental Protection Agency resilience grant for work at the Monroe Water Treatment Plant, including backup generation and control-system improvements. The grant is intended to improve the plant’s ability to operate through power interruptions and other system disruptions.
Separate capital projects supported through the 2026 drinking-water rate increase include treatment plant improvements, replacement of aging water mains, pumping and storage upgrades, treatment-process improvements, and modernization of controls and monitoring equipment. The updated water rates were approved by the Utilities Service Board and Bloomington Common Council in September 2025. The increase took effect in August 2026.
If you have questions or concerns, please contact City of Bloomington Utilities at 812-349-3930 or by email at wq@bloomington.in.gov.
