City to Begin Update to Strengthen Drinking Water Treatment
Published on February 19, 2026
The City of Kalamazoo is implementing a treatment technique change to the public drinking water system to further strengthen corrosion control and protect public health.
Since 1956, the City has used phosphate treatment to control corrosion and sequester naturally occurring iron in drinking water. After nearly a decade of study and testing, the City, working in cooperation with the Michigan Department of Environment, Great Lakes, and Energy (EGLE), will transition to a more optimized corrosion control approach tailored to Kalamazoo’s groundwater chemistry and water system;
The change will be implemented through a phased rollout, according to a service-area map and schedule, following upgrades at all 13 drinking water treatment plants in the system.
The City is updating the type of phosphate used in drinking water treatment. The existing treatment primarily uses polyphosphate, which is effective at sequestering iron. The new treatment will primarily use orthophosphate, which is more effective at forming a protective lining on the inside of pipes.
This protective lining reduces direct contact between water and metal surfaces, significantly lowering the risk of metals, especially lead, leaching into drinking water from older pipes, service lines, plumbing solder, or fixtures.
While the new treatment focuses on orthophosphate for corrosion control, it will still include a polyphosphate component, meaning iron sequestration benefits will continue.
As part of the project, phosphate storage and injection systems are being upgraded to current standards, including the addition of modern automation to ensure consistent and precise treatment.
Corrosion control is a safe, proven, and commonly used water treatment process across the country. It is one of the most effective tools water systems have to protect against lead exposure, even in communities with older infrastructure. Optimizing corrosion control helps ensure that drinking water remains safe as it travels from treatment plants through distribution pipes and into homes and businesses.
In addition to this treatment update, the City of Kalamazoo remains committed to replacing every lead water service line in the system. Optimized corrosion control provides an added layer of protection for customers while lead service line replacement work continues, reducing potential exposure during the transition to a fully lead-free system.
This treatment update follows nearly 10 years of study, beginning in 2016, including chemical analysis, two rounds of solubility testing, coupon rack testing, and evaluation of treatment performance on steel, brass, galvanized metal, lead, and other materials found in the system.
Studies supporting this change are publicly available at www.kalamazoocity.org/CorrosionControl.
“This update strengthens corrosion control in a way that reflects nearly a decade of study and testing,” said James Baker, Public Services Director. “It’s a proven approach that helps protect our customers from lead while we continue the work of replacing every lead service line in the system.”
The total project investment is approximately $13 million, funded through the City’s water utility and supported by customer water rates, which are reinvested into maintaining, improving, and modernizing the drinking water system to ensure long-term safe, reliable service.
During the transition, some customers may notice temporary aesthetic changes, such as discolored water. These changes are not a health concern and may occur when mineral deposits inside pipes are disturbed. Discoloration does not affect the safety of the drinking water.
Customers can find a searchable rollout map at www.kalamazoocity.org/CorrosionControl.
In many cases, discoloration clears on its own. However, if water use is low, water may remain in service lines or household plumbing until flushed through normal use. In some situations, City crews may need to perform localized water main flushing to restore normal water appearance.
Residents and businesses experiencing water quality concerns are encouraged to report them promptly by calling 311 within the City limits or (269) 337-8000 from outside City limits. Reporting issues allows the City to respond quickly and take appropriate action when needed.
The City of Kalamazoo remains committed to providing safe, reliable drinking water and will continue working closely with EGLE throughout the phased implementation of this treatment update.