City of Caseville Discolored Water Update: Summer 2026
City of Caseville
Discolored Water – Summer 2026 Update
What are the results and recommendations from the EPA Engineering Study?
The City of Caseville received assistance from the U.S. Environmental Protection Agency’s (EPA) Water Technical Assistance (WaterTA) Program. EPA and their contractor completed a water quality study in conjunction with a comprehensive engineering study in 2025 to evaluate the cause of the discolored water and to propose solutions. Results and recommendations were finalized in an April 2026 Preliminary Engineering Report (PER).
The primary cause of the discolored water is related to manganese in the source water and the aging intake bed in Saginaw Bay which is also contributing to water hardness. The PER sampling results indicate an exceedance of the EPA’s secondary Maximum Contaminant Level (sMCL) for manganese in the distribution system. Secondary sMCLs are not health-based or enforceable but establish guidelines to assist public water systems in managing aesthetic considerations like taste, odor and appearance. Despite the aesthetic issues, the City continues to meet the strict health standards and treatment requirements of the Safe Drinking Water Act and complies with all water sampling requirements. The City has also increased voluntary monitoring efforts and data collection. If water testing ever shows the water does not meet health standards, customers will be notified immediately.
To address the discoloration and high levels of water hardness, the PER recommends implementing intake bed bypass modifications with pre-oxidation and dissolved air flotation (DAF) with coagulant prior to microfiltration. Pre-oxidation promotes the oxidation of dissolved metals like manganese to assist the removal efficiency during the microfiltration process. Bypassing the current intake will reduce water hardness, iron and manganese levels in the raw water by pulling directly from Saginaw Bay.
When will the recommended solution be implemented?
In the short term, the City is working with an engineering firm and the Department of Environment, Great Lakes and Energy (EGLE) to permit and install a pre-oxidation treatment system that could potentially be utilized during summer 2026. This treatment system will reduce manganese levels in the distribution system which are directly related to the discolored water. The City is also proactively flushing to waste incoming raw water at plant startup each day to improve water quality.
Solutions to the aging intake bed and water hardness are planned to be implemented within the next five years. The DAF treatment system will require pilot testing over 2026 and 2027 with the goal of covering several seasonal water quality changes. A detailed design of the full-scale treatment facility could be completed by 2028. Construction for the new facility could take two years through 2030.
Where can I find the results and recommendations from the MDHHS investigation?
In 2025, the Michigan Department of Health and Human Services (MDHHS) completed an investigation of the discolored water, which included sampling at homes throughout the City of Caseville, Caseville Township and the Village of Pigeon. There were no findings of immediate concern to public health. MDHHS is finalizing its report, which will be made public and posted to its website in 2026.
Who can I contact with questions?
You can report a drinking water concern at the link below:
https://www.michigan.gov/egle/about/organization/clean-water-public-advocate/report
If you have health-related questions, you can call the MDHHS Environmental Health Hotline at 800-648-6942.