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Page last updated on May 31, 2023 at 10:04 am

How Bloomington protects your drinking water

Bloomington has a surface water source for drinking water, Lake Monroe. The Monroe Water Treatment Plant (MWTP) filters and cleans the water for public distribution. The MWTP is operated by the City of Bloomington Utilities Department (CBU). The MWTP is a conventional settling/filtration facility and has several stages of disinfection before the water is sent out into the distribution system.

The United States Environmental Protection Agency develops criteria for determining when water has become unsafe for people and wildlife using the latest scientific knowledge. For help interpreting water quality measurements, please see this EPA site.

For help with selecting a home water filtration system, please see this guide to selecting a water treatment system from the NSF.

Bloomington's Water

Where does Bloomington's water come from?

Bloomington relies on surface water as its drinking water source, Lake Monroe. Also known as Monroe Reservoir, Lake Monroe is the largest man-made body of water in Indiana at 10,750 acres. The watershed drainage area for Lake Monroe is 441 square miles and discharges into Salt Creek.

The Monroe Water Treatment Plant currently averages pumping 15 million gallons per day (MGD). This number has been as high as 23 MGD in warmer months. The Monroe Water Treatment Plant is a conventional rapid sand filtration plant.

Besides flood control and drinking water supply, Lake Monroe is used for recreational purposes.

Where does water get treated?

Bloomington's drinking water is treated at the Monroe Water Treatment Plant.

For sanitary sewer, Bloomington has 2 wastewater treatment plants, Dillman Road Wastewater Treatment Plant and Blucher Poole Wastewater Treatment Plant. Treated water from Dillman enters into Clear Creek. Treated water from Blucher Poole enters into Bean Blossom Creek.

Stormwater runoff is not treated. Instead, it is collected and funneled via inlets, culverts, ditches, swales, etc. to local creeks, then on to the White River, Mississippi River, all the way to the Gulf of Mexico! 

Taste and Odor Compounds

During especially warm and dry periods, the taste and odor producing organic compounds methylisoborneol (MIB) and geosmin may be present in the drinking water. These two compounds are not harmful to human health. Rather, the presence of MIB and geosmin negatively affect the drinking water's aesthetics, causing an earthy, musty taste and smell. CBU uses various methods to decrease these compounds during water purification, but at times they may persist after treatment. One method of masking the taste and smell in drinking water is to fill a pitcher or jug of water, add lemon or fruit wedges, and store it in the refrigerator. 

To access the most recent taste and odor compound data view our latest water quality data.

CBU tests drinking water multiple times each day for many different quality parameters at sites across the distribution system and at the water treatment plant to ensure the water continues to be safe to drink.  Annual water quality reports and current data are available at

Customers who have further questions should contact CBU’s water quality team. The 24-hour line is 812-339-1444 or customers can send an alert through the UReport system at

Hardness of Bloomington water

Hardness in water is caused by calcium and magnesium, two non-toxic minerals. Water is considered hard when there is calcium or magnesium present because these minerals make it hard to form a lather or suds, which makes it "hard" to wash. Water with no calcium or magnesium is considered soft (and easier to wash with). Bloomington water averages 50mg of calcium carbonate per liter which is considered soft water. Learn about water hardness patterns throughout the United States.

Learn about drinking water standards and contaminants.

Bloomington's Watersheds

A watershed is the area of land that drains into a body of water. The watershed also includes the creeks and other water bodies in the area. The quality of a water source depends greatly upon the watershed. The contaminants in a watershed will end up in the surface water body. This is the reason that watershed management is important. If the pollutants are controlled throughout a watershed, the body of water is protected as well.