Illinois American Water Completes Major Improvements, Enhancements to Regional Water Treatment Plant Near East St. Louis

Since 2019, $157 million has been invested in major upgrades and enhancements to the Metro East regional water treatment plant that focus on service reliability, water quality and operational efficiencies, while incorporating state-of-the-art environmental technology.

BELLEVILLE, Ill., Dec. 9, 2025 /PRNewswire/ -- In 2025, Illinois American Water's Interurban (Metro East) District completed the final stages of significant upgrades and enhancements to its historic water treatment plant on the Mississippi River near East St. Louis.

The original water plant was built in the late 1800s to serve the City of East St. Louis and small surrounding communities only. The plant has been updated and expanded many times over the past 130 years to serve a regional customer base in the Metro East. The water treatment plant provides service to an estimated 75,000 direct customers (metered), or a population of more than 350,000 in the Metro East.

"The major investments to our East St. Louis plant over the past six years are strategic, significant and sustainable," said Rebecca Losli, President, Illinois American Water. "The projects position us to continue providing quality water service in the Metro East that meets or surpasses regulatory quality standards."

The water treatment plant provides water directly to customers in the following communities: Belleville, Brooklyn, Cahokia Heights, East St. Louis, Fairmont City, Sauget, Shiloh and Swansea. The water treatment plant provides water to the following communities on a sale-for-resale (wholesale) basis: O'Fallon, Cahokia Heights, Caseyville, Columbia, Fairview Heights, Millstadt and Scott Air Force Base.

Situated along the east bank of the Mississippi River near the Stan Musial Veterans Memorial Bridge, the water treatment plant's original water basins were installed in 1887. Today, the water plant meets a daily demand of approximately 39.3 million gallons with maximum daily demand of approximately 47.70 million gallons.

"There have been many expansions, renovations and updates in the last century to our East St. Louis water treatment plant to help ensure safe, clean, reliable, safe water service to our Metro East customers," continued Losli. "These upgrades were completed strategically over six years and improve our operational efficiencies, safety and our environmental footprint."

Highlights of the renovation and improvements at the water treatment plant:

• Construction of an elevated water storage tank.
• New raw water pumps and variable frequency drives at the water intake structure on the Mississippi River.
• New diesel, high service backup pump which runs in event of a power outage.
• Two clear wells which triples storage capacity at the plant.
• New ultraviolet water treatment system and storage building. This is an additional layer in the water treatment process at the surface-water plant. Ultraviolet water treatment effectively deactivates bacteria, viruses, and other pathogens in raw, untreated water from the river. This additional water treatment step is chemical-free and environmentally friendly.
• Upgraded chemical feed systems from gas to liquid enhances employee safety and public safety for surrounding communities. The switch from gas to liquid chemicals also enhances water quality throughout the 26-mile distribution system in the Metro East.
• Upgraded security and fire alarm systems.
• Increased capacity of the backup diesel power generation.
• New residual pump station and concrete residuals pond.

Some older buildings at the water treatment plant are no longer being used and are planned to be razed over the next few years.

Said Losli, "Our focus at the East St. Louis water treatment plant is an example of continuous investments and improvements to meet the demands of today's customers and planning for the future. Continued investments are needed across the nation to maintain critical water and wastewater infrastructure."

There is an economic ripple effect on investment in water and wastewater infrastructure. According to the U.S. Water Alliance, every $1 million invested in water and wastewater infrastructure, 10 jobs are created. Since 2019, the major investments and updates at the water treatment plant brought more than 1,500 jobs to the Metro East region. All construction work was completed by union contractors and employees. 

The East St. Louis water treatment plant is an award-winning member of the Partnership for Safe Water. This national recognition is given to fewer than 150 water treatment plants in the United States. The Partnership is a national voluntary initiative developed by U.S. Environmental Protection Agency (EPA) and other water organizations to recognize water suppliers that consistently achieve water treatment standards that go above and beyond EPA regulatory requirements. As a member of the program, water utilities pledge to continually improve their treatment operations and undergo a rigorous review that includes a four-phase self-assessment and peer-review process.

About American Water 
American Water (NYSE: AWK) is the largest regulated water and wastewater utility company in the United States. With a history dating back to 1886, We Keep Life Flowing® by providing safe, clean, reliable and affordable drinking water and wastewater services to more than 14 million people with regulated operations in 14 states and on 18 military installations. American Water's 6,700 talented professionals leverage their significant expertise and the company's national size and scale to achieve excellent outcomes for the benefit of customers, employees, investors and other stakeholders.

For more information, visit amwater.com and join American Water on LinkedIn, Facebook, X and Instagram.

About Illinois American Water
Illinois American Water, a subsidiary of American Water (NYSE:AWK), is the largest regulated water utility in the state, providing safe, clean, and reliable water and wastewater services to approximately 1.3 million people. American Water also operates a quality control and research laboratory in Belleville.

SOURCE American Water