Skip Navigation LinksHome > Water > Water Quality

Drinking Water Quality

Lake Springfield is the source of Springfield's domestic water supply. It provides drinking water to approximately 147,750 people who, altogether, use an average of about 22 million gallons of water each day. Water taken from the lake undergoes a rigorous purification and testing process—to ensure it is free of harmful bacteria and particulate matter—before being distributed for domestic use to the utility's water customers.


Water Testing

Throughout the water purification process, chemists and plant operators at the CWLP Water Purification Plant perform approximately 70 analytical tests on the purified water each day to ensure it meets or exceeds Illinois Environmental Protection Agency (IEPA) standards for microbiological and chemical content. Many samples are also sent to the IEPA for chemical analysis. In this way the utility assures that the product leaving the Purification Plant will be of the highest possible quality.

Altogether the levels of about 150 different chemicals and water quality parameters are checked and the analytical results are compared to the maximum contaminant level (MCL) allowed for chemicals by the IEPA. As of the most recent test dates, in all cases, chemical levels in Springfield's drinking water fell below the MCLs established by the IEPA.

Among the chemicals tested for are: alachlor, ammonia, arsenic, atrazine, barium, benzene, calcium, carbon tetrachloride, chlordane, chlorine, cyanide, DDT, heptachlor, iron, lead, lindane, magnesium, manganese, mercury, nickel, nitrate, selenium, sodium, sulfate, vinyl chloride, and zinc.
Lead Safety

Water Quality Reports

Each spring, CWLP prepares a Water Quality Report for our customers detailing the results of drinking water tests performed during the preceding year. An announcement of the availability of the annual report is enclosed in the May or June billing envelopes of all customers who receive a CWLP bill. The report is available online or, upon request, in paper form to any CWLP water consumer. See our most recent Water Quality Reports online below.
WQR2013 WQR2014 WQR2015 WQR2016 WQR2017 WQR2018 WQR2019 WQR2020

To obtain a printed copy of the report by mail, call the Water Purification Plant, 217.757.8630, or email the Public Information Office at publicinformation@cwlp.com.

Preventing Backflow Contamination

In spite of CWLP's efforts to produce pure, safe drinking water, Springfield's drinking water can be placed at risk by contaminants that "backflow" into the system from our customers' homes or businesses. It's up to all customers to take the necessary steps to protect our water supply from this type of problem by making sure their plumbing systems are equipped with working backflow prevention devices. For more information about backflow contamination and how you can help prevent it, see our online pamphlet below.
Protecting Against Backflow Contamination Pamphlet Take Our Survey

Distribution System Flushing

The Springfield Fire Department, in coordination with CWLP conducts annual testing of the fire hydrants to ensure each is operating efficiently for fire protection purposes. Water can become discolored in service areas located in the vicinity of the hydrant tests.

If discoloration occurs or during testing to avoid issues, residents should run water from an outdoor hose connection preferably, or through an indoor tap, until the water turns clear. Clothes washing should be delayed until the tap water runs clear to avoid discoloration. In most instances, the water will clear in approximately five minutes.

For information on locations and times for the annual hydrant testing, residents may call the Springfield Fire Department at 788-8474. CWLP customers may call Water Dispatch at 789-2323 ext. 2 if discoloration persists or for any other questions on water quality.

Lake Turnover Can Cause Taste & Odor In Drinking Water

Lake turnover is common occurrence that happens with all lake water most often in the fall and sometimes the spring with temperature changes. When a lake turnover occurs some may notice what is described an earthy or musty taste and smell to the drinking water. The compounds that cause the taste and odor issues are not considered a risk to public health and do not diminish the ability of a water provider to meet water quality guidelines for health standards.

Lake turnover occurs when the water from the top of the lake changes places with the water on the bottom of the lake. With fall temperature changes, as water cools on top of the lake, it becomes more dense, causing it to sink. This dense water forces the water from the bottom to rise. Lack of water movement in a reservoir can exacerbate the turnover effect and increase the taste and odor increasing compounds. For Lake Springfield, the lack of water movement in the reservoir including with nonoperation of Dallman Power Plant Units 31, 32 and 33, appears to correlate with exacerbation of the higher levels of algal compounds and turnover in Fall 2021.

To ensure CWLP drinking water is safe to drink, and meeting or exceeding all regulatory standards, the utility works hard to meet customer expectations for the water’s aesthetic characteristics – its taste, odor and appearance. CWLP feeds powdered activated carbon to reduce taste and odor compounds in the finished drinking water. To further address the taste and odor issues, the Water Plant can increase its Powder Activated Carbon in the treatment process and alter the depth of its raw water intake in an attempt to minimize the issue. Water Distribution can also enact distribution system flushing to move water.

Customers sensitive to the taste and odor issues may find drinking chilled water from a pitcher after refrigeration may be more pleasing. Customers with taste and odor issues can make a report to Water Dispatch at 217.789.2323 ext. 2 or email publicinformation@cwlp.com.

Drinking Water Taste and Odor FAQS

What is making my water taste or smell earthy or musty?
Lake turnover, a normal event for surface water supplies, occurs when the water from the top of the lake changes places with the water on the bottom of the lake. With fall temperature changes, as water cools on top of the lake, it becomes more dense, causing it to sink. This dense water forces the water from the bottom to rise. Lack of water movement in a reservoir can exacerbate the turnover effect and increase the taste and odor increasing compounds. The lack of water movement in the reservoir including with nonoperation of Dallman Power Plant Units 31, 32 and 33 appears to correlate with exacerbation of the higher levels of algal compounds and turnover.

With lake turnover, algal compounds from naturally occurring blue green algae result in a change in the the taste and odor. The algal compounds, Geosmin and Methylisoborneol (MIB) found in naturally occurring blue green algae have been identified as the cause for the taste and odor.

Video: See our presentation to the City Council on Tuesday, September 21, with more details on the issue and the steps we took in Fall of 2021 to address the problem here https://youtu.be/08iB0LQkKn4?t=2353.

Is my water safe to drink during lake turnover?
Yes. The algal compounds do not impact drinking water safety. Although the water can have an off taste or odor to some described often as earthy or musty, it is safe to drink. Chilling tap water before drinking can reduce taste issue.

What does CWLP use to make the water taste better?
The Water Plant can increased its Powder Activated Carbon in the treatment process, alter the depth of its raw water intake and conduct plant washouts to address when the issue arises. Water Distribution crews have also completed one phase of system distribution system flushing and a second phase is underway now. Year-round CWLP and its partners implement Best Management Practices in the Lake Springfield Watershed to reduce runoff and nutrients into the reservoir, which include those that cause algal compounds to increase. In the future, the utility may seek to implement lake aeration and flow equipment to reduce the negative impacts from turnover.

Is there anything I can do to make the water taste better?
Chilling tap water before drinking can reduce taste issues for some. Adding a slice of lemon to the water sometimes helps as well. A home charcoal filter may help but it is not likely to remove the taste or odor entirely. The charcoal in a home filter uses the same material (granular activated carbon) as the water treatment plant does, which is only able to resolve most but not all, of the taste and odor causing compounds.

Where can I report water issues or ask questions?
Contact our 24-hour Water Dispatch at 217.789.2323 ext. 2 and make a report with your contact information and address or email PublicInformation@cwlp.com.