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Safe, reliable water plays a vital role in all our daily lives, keeping our community healthy, supporting our economy, and contributing to our overall quality of life. That’s why Cleveland Water has a comprehensive water treatment process in place to make sure our customers have access to safe, quality water every day.

Our commitment to providing our customers with quality drinking water is proven through our treatment process. We use a conventional treatment process at all four of our plants to ensure our water meets federal and state requirements as well as the higher industry standards of the Partnership for Safe Water. This process involves the primary steps of coagulation, flocculation, sedimentation, filtration, disinfection, and finishing to take water from Lake Erie and turn it into clean, safe drinking water.

Treatment Process Overview

Cleveland Water Treatment Process Diagram



Located 3 to 5 miles offshore in Lake Erie, a crib protects the top of the pipe into which lake water flows, preventing large pieces of debris from entering the pipe.


Intake Tunnel

Beneath the bed of Lake Erie, an intake tunnel, between 7 to 10 feet in diameter and several miles long, brings water to the treatment plant. Near the shore end of the tunnel, we add a chemical called Potassium Permanganate (A). Potassium Permanganate is an oxidant that helps more effectively remove particulates. It also helps control taste, odor, and color as well as quagga mussels and algae.



Screens filter out mussel shells, fish, and other large debris before the water enters the treatment process.


Raw Water Pumps

Raw water pumps pull in the water from Lake Erie to begin the treatment process. At the raw water pumps we add Powdered Activated Carbon (B). It absorbs organic material that can cause unpleasant tastes and odors. Contaminants attach themselves to the carbon granules and settle out in the sedimentation and filtration steps.


Rapid Mix

During the rapid mix step, Aluminum Sulfate (C), or Alum, is added and quickly mixed into the water. Alum is added as a coagulant to help small particles stick together so that they can be removed more easily.



Water moves through three zones of mixing, with each zone mixing at a slower speed than the one before to allow organic and inorganic material to clump together as floc. 



Water moves slowly through large settling basins where heavy clumps of floc settle to the bottom of the tanks and are removed. The cleaner water passes through the top of the tank to the next phase.



At the filters, gravity pulls water through filter media made of two feet of anthracite over one foot of sand to remove finer impurities.


Disinfection & Finishing

At this step, we add Chlorine (D) – to kill pathogens, Fluoride (E) – to promote dental health, and Orthophosphate (F) – to prevent pipe corrosion. The water then slowly moves through the finished water reservoir to ensure chlorine has adequate time to kill all bacteria and viruses.


Finished Water Pumps

The finished water is pumped through the distribution system to customers. Throughout the treatment process, we test the water to make sure each stage is working effectively and only safe, clean water is produced and delivered to customers.