The system serves over 44,000 people through 4,700 metered water connections and about 2,500 wastewater connections.
Aqua America has committed to freeze rates for NMU customers through June 2020, excluding any purchased-water increases from the current provider.
The company will also invest $10m to build an interconnection with Glenview to purchase Lake Michigan water from Glenview at a lower price than the estimated rate of the current provider.
The Village of Glenview owned NMU for 17 years and provided repairs as well as enhancements including the replacement of underground water and sanitary sewer pipes and system maintenance works.
Aqua America chairman and CEO Nicholas DeBenedictis said: "Aqua Illinois is excited to be able to serve the residents and businesses of North Maine with quality water and wastewater services, reasonable rates and excellent customer service.
"With more than 125 years of experience in the water industry, we have the operational capacity, technical expertise and resources needed to meet the needs of NMU customers.
Aqua Illinois delivers water and wastewater service to around 175,000 people in 13 counties across Illinois.
