Straight from the Tap

How Cleveland Water is Prepared for Lake Erie Summer Water Quality


Every summer, as the temperature of Lake Erie slowly climbs in advance of the annual lake stratification, Cleveland Water closely monitors the lake's water quality for any issues that might follow.

While Lake Erie water levels are currently breaking all records, Lake Erie water temperatures are just average. But as the water gets warm enough, and if excess nutrients are present, blooms of an unwanted organism can occur.

From May to October, Cleveland Water performs numerous tests and conducts constant monitoring on the lookout for cyanobacteria – commonly referred to as blue-green algae. Not all algae are harmful and different types grow all year long. Generally, algae are an important part of the ecological food chain.

Cyanobacteria, however, starts to bloom in early spring and grows best when water temperature ranges from 77 to 91⁰F. Rapidly growing blooms, called harmful algal blooms (HABs), can produce toxins that are harmful to animals and humans.

Cleveland Water has a history of not detecting cyanobacteria toxins in lake water coming into our plants. This is due to the location of our water intakes between 3 and 5 miles offshore in water that is deeper and colder.

The offshore distance of our intakes means they are less likely to experience runoff of nutrient-rich water that can exacerbate HABs. And their location in deeper water and colder water means HABs are less likely to form because most cyanobacteria need warmer water and sunlight to grow and reproduce.

Even so, we vigilantly monitor Lake Erie and regularly test its water.

Year-round, we monitor Lake Erie for specific parameters related to all forms of algae and cyanobacteria through devices called sondes. Sondes are mounted on buoys out in the lake and in our intakes so that data can be collected in advance of water reaching our treatment plants. This advanced warning is very important as it allows us to adjust the treatment process as raw water conditions dictate. We also use data from partners to track the development and movement of HABs, like satellite imagery and bloom forecasts from NOAA.

We regularly test lake water May through October, when HABs are most likely to occur, for toxins that cyanobacteria can sometimes produce. We perform in-house microscope identification and send samples to a third party laboratory for extensive identification and quantification of cyanobacteria and algae cells.

Cleveland Water has been performing these tests since 2010 and has built up an extensive data set that helps us to better understand and predict the conditions that cause HABs. And if less than desirable water does enter our intakes, multiple barriers in our water treatment process help ensure the only thing that makes it to your tap is clean, safe drinking water.

Our Water Quality Report details the testing results and quality of our drinking water. The report is found here. The complete Average Chemical Values Summary for 2018 is found here. And if you have questions about the water quality in your home, please call us at 216-664-2639.