Water Treatment

Milwaukee’s drinking water comes from Lake Michigan and is treated at two facilities: the Linnwood Water Treatment Plant on the north side and the Howard Avenue Water Treatment Plant on the south side. Water is drawn from deep lake intakes located more than a mile offshore, where it is less affected by surface conditions.

Before water reaches your home, it goes through a multi-step treatment process designed to remove contaminants and protect public health.

The primary form of disinfection is ozone gas. Ozone is created by applying electricity to oxygen and is bubbled through the water in large tanks. This process destroys illness-causing microorganisms such as Cryptosporidium and Giardia and helps improve taste and odor. Using ozone also reduces the formation of certain disinfection byproducts.

Next, particles are removed through a series of steps including coagulation, flocculation, settling, and filtration.

Additional treatment steps include:

• Chlorine, added as a secondary disinfectant
• Fluoride, to help prevent tooth decay
• Corrosion control, to reduce the risk of lead entering water from pipes
• Chloramine, to maintain disinfection as water moves through the distribution system

State regulations require a detectable level of disinfectant throughout the system to maintain protection against bacteria.

All treatment chemicals are certified safe for drinking water. Both treatment plants use advanced monitoring systems to track water quality and operations in real time.

After treatment, water is continuously tested at the plants and throughout the distribution system to ensure it meets all safety standards. Learn more about our monitoring program.

How long does treatment take?

It takes approximately 22 hours for water to move from Lake Michigan through the Linnwood Water Treatment Plant. The time it takes to reach your home depends on your distance from the plant and overall system demand.