State and local leaders highlight $78.7 million investment to upgrade Mackinac Island Wastewater Treatment Plant

EGLE hosts tour during Mackinac Policy Conference to showcase the impact of water infrastructure investments

MACKINAC ISLAND, Mich.—Today, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) Director Phil Roos joined state and local leaders during the Mackinac Policy Conference to highlight the $78.7 million Mackinac Island Wastewater Treatment Plant (WWTP) Improvement Project. The event featured a tour of the plant and an update on construction progress, emphasizing how the state’s continued investment in water infrastructure benefits communities, creates jobs and protects Michigan’s world-class water resources.

Originally constructed in 1970, the Mackinac Island WWTP has undergone significant upgrades to accommodate the island's growing population and tourism demands. The WWTP, which serves a population ranging from 492 in the winter to over 20,000 in the summer, previously struggled to meet environmental and capacity standards. The upgraded plant will provide better wastewater treatment, expand capacity and improve water quality on the island, ultimately supporting sustainable growth.

"Investing in water infrastructure is critical to ensuring the health and safety of Michigan’s communities," said Director Roos. "This project is a shining example of how strategic investments in our water systems provide long-term benefits for both residents and visitors, while also contributing to Michigan’s ongoing efforts to improve water quality."

The WWTP Improvement Project aims to expand and modernize the wastewater treatment plant, with major upgrades like automated screening, grit removal and advanced treatment systems such as moving bed biofilm reactors and UV disinfection. Expanded capacity will allow the plant to handle seasonal surges in wastewater, while new pumps, blowers and controls will improve water quality and stormwater management. Collaboration between EGLE, Mackinac Island and the Mackinac State Historic Parks was essential to securing additional property for expanding the WWTP footprint.

"We appreciate the support the community has received from the EGLE State Revolving fund loans, ARP grants, and additional State appropriations for our new Wastewater Treatment Plant," said Mackinac Island Mayor Margaret Doud. "The project is a critical need for the Island’s infrastructure. This will be a great improvement to the Mackinac Island Community that all will greatly benefit from. We would like to thank everyone involved for supporting our beautiful Island, a true Gem, which is enjoyed by many and will be for generations to come."

The Mackinac Island WWTP upgrade was made possible through a combination of funding sources, including a $24 million Clean Water State Revolving Fund (CWSRF) loan, a $15 million American Rescue Plan (ARP) grant and a $39.7 million state appropriation grant in 2023. These funds will allow the facility to implement wastewater treatment processes and ensure more efficient and environmentally responsible operations.

"Infrastructure projects on Mackinac Island are not cheap, nor are they easy. However, these services are critical in serving both the seasonal and year-round Mackinac Island communities, the State Park, and the numerous guests our community serves," said Mackinac Island Director of Public Works Allen Burt. "Without the assistance of EGLE State Revolving Fund loans, ARP grants, and additional State appropriations, the residents of the City of Mackinac Island would be unable to support these much-needed system updates.  I thank everyone who has come together to support Mackinac Island as the special place it is not only to our local community, but to the entire State of Michigan."

Governor Whitmer’s Fiscal Year (FY) 2026 Executive Recommendation Budget continues to build on these investments, providing $50 million in one-time funds to support lead service line replacement and upgrades to water systems. Additionally, $30 million in annual funding will be directed to support lead service line replacements, stormwater management and wastewater infrastructure improvements. Another $5.95 million is dedicated to strengthening the implementation of the Safe Drinking Water Act to ensure safe water for all Michigan families.

"There is immense public value in making low-interest loans available for local communities to upgrade their water systems," said State Representative Parker Fairbairn, R-Harbor Springs. "The Clean Water State Revolving Fund helps to protect our lakes, rivers, and streams and thereby safeguards public health. This program allows them the resources to make critical and sometimes overdue updates to their infrastructure. The Revolving Fund gives communities the flexibility to make these necessary investments without having to pay much higher interest rates of commercially available loans."

Since 2019, the Whitmer-Gilchrist administration has invested more than $5.3 billion in water infrastructure projects, including lead service line replacement and water quality improvements. These efforts are part of a broader strategy to ensure all Michigan communities have access to safe, clean drinking water.

For more information on EGLE’s water infrastructure initiatives, visit Michigan.gov/MiCleanWaterPlan.