Straight from the Tap

The Science Behind Water Quality


Delivering safe, quality drinking water to our customers is important. It takes a lot of science and a lot of engineering – from chemistry, biology and freshwater ecology to civil, sanitary and electrical engineering. Understanding laws, regulations, and industry standards are also critical to ensuring the water we provide our customers is safe.

Each day, we draw hundreds of samples at each of our four water treatment plants. We test the raw water coming into the plant, the water as its being treated, and the finished water ready for distribution and consumption. Every two hours, the water is tested by one of our certified operators to ensure that the correct chemical feed rates are being added. Feed rates are adjusted as needed based on the ever-changing chemistry and biology of Lake Erie. The tests include pH (a measure of the amount of hydrogen ions), temperature, chlorine, phosphate, turbidity, fluoride, and of course, taste. Throughout the course of a typical year, we will run at least 160,000 tests on our water before it gets to you. That’s more than 400 tests daily.

After the water is processed, it is still monitored at the reservoirs and tested throughout the 5,300 miles of piping and water tanks in our distribution system. These tests are more technical in nature and meet all Ohio EPA drinking water standards. The more advanced chemical analyses are conducted by Cleveland Water’s Ohio EPA certified chemists at our state certified laboratories. These tests include more than 400 bacteria, 100 TOC (total organic carbon), 16 DBP (disinfection by products), 100 anions (sulfate, chloride, nitrates, nitrites, and phosphates), and 1000 chlorine readings on a monthly basis. We also monitor lead and copper and orthophosphate in the system.

This testing process is very important to ensure that nothing but the best water is being delivered to you.

In addition, we also have several continuous analyzers that monitor raw, partially treated, and fully treated water every minute of every day. Many of these monitors are intended to meet regulatory requirements. Some of them are strictly for our own information to ensure quality control throughout the treatment process. Over the past 20 years, we have spent over $600 million to ensure we have state-of-the-art, modernized treatment facilities as well as state-of-the-art monitoring equipment and process control systems.

We are now developing additional means of monitoring the water through specialized equipment called sondes. These continuous sensors are mounted to buoys at strategic locations in Lake Erie and give us real-time information about lake conditions. This information gives us an advanced warning of potential problems due to concerns like harmful algal blooms and Dead Zone water.

Visit our annual Drinking Water Week Open House in early May to learn more about the science behind water quality. Find more information about our 2017 Open House and register for a tour at here