After 1993: The Reconstruction of a System

By: Michelle Gonzalez and Barbara Gonzalez

After the 1993 cryptosporidium outbreak, Milwaukee placed more attention to the process of the water treatment. This caused the city to change filtration and management systems to provide residents with safe water in order to prevent future incidents similar to the outbreak.  

Carrie Lewis

With so much uncertainty from every corner, Carrie Lewis came into her position as Superintendent of the Milwaukee Water Works, knowing the utility had lost the confidence of Milwaukee’s residents.

“I came in about two years after the outbreak and there were still people who were not drinking city water because they didn’t trust it,” she said. “People had been hurt, they felt let down by their drinking water and it took a  long time for them to believe that we knew what we were doing again.”

Lewis said that it took at least a decade to regain the trust of Milwaukee citizens, but noted that it was a very gradual process, describing it as taking one baby step at a time. The utility would talk to school groups, community organizations, and consult with elected officials to connect with the people of Milwaukee.

When it came to the reconstruction of the system, the utility invested $89 million dollars in improvements, taking a three step approach, starting with hiring a more experienced staff.  While it was a hefty sum for one business to take on, the three-step proposal for the long term solution for the Milwaukee Water Works was actually determined very early on while the boil advisory was still in place.

Lewis also notes that they now have a very strong partnership with the Milwaukee Health Department in comparison to 1993.

“Even though the water department and the health department are literally in the same building, the people who worked for each one of them didn’t talk to the other one,” Lewis said.  “Now ever since 1993, every three months we have met  with the health department and talked about areas of emerging concern and mutual stuff has really helped enormously.”

Photo by Carrie Lewis

Another major change was the extension of pipe for the Howard Avenue Water Treatment further into the lake. This was adjusted in order to move the pipes further away from potential problems such as land contaminants, that might be coming directly from the Milwaukee river.

The water from a faucet follows a process of filtration before it reaches the pipes of your home. The water filtration system in Milwaukee did not change until approximately 63 years later, when the outbreak occurred.

Photo Courtesy of Carrie Lewis

The city of Milwaukee improved the water filtration system by transforming the filter system as well as changing the management of the filters. According to Lewis, sand filtration  was first used to filter out particles from the flowing water. It consisted of three feet of sand and rocks, however, the new filtration system is made of anthracite coal, high in carbon content, which is added on top of sand.  This multi-layered filtration system was implemented in both Milwaukee water plants. They effectively remove small particles from the water and help reduce the risk of cryptosporidium ending up in the water coming from your faucet.

Photo by Carrie Lewis

Ozonation is used during the water treatment process. Chlorine was first used to try to disinfect cryptosporidium, but research findings show that crypto was not affected by chlorine at all.

“There is only one known way, in the world to proactively prevent cryptosporidium from

contaminating your water and that’s by using a process called ozonation,” Nannis said.

The ozone gas breaks down microorganisms and serves as the primary disinfectant for crypto. Ozone  can break down the hard shells that surrounds the parasite,  unlike

Photo by Carrie Lewis

Photo by Carrie Lewis


Automation and online monitoring are done not once, but many times to ensure there are no leaks or problems concerning the filtration system.

Online monitoring and automation are new developed  systems that were not used before.

“In fact, it’s almost impossible to even imagine how we did things back in 1993, but it was quite normal every two hours for a person who worked in the lab to go somewhere in the plant, grab a sample of water, carry it back to the lab and analyze it in the lab and have those results,” Lewis said. “Now we have instruments that do that for us every five seconds and take the readings instantly and alert the operators if anything is crazy, so monitoring improvements and moderation have made huge advances in how we’re able to treat water…”

According to Lewis, in the past 12 years, crypto was found twice in the raw water. Slowly, the residents of Milwaukee have started regaining the trust they once lost in 1993 and the city of Milwaukee’s recognition of having fresh, clean water.

Photo by Mckinley Marina/Creative Commons

Antonio Garcia has been studying the science of water since his undergraduate in McNair.

He is a graduate from UW-Madison and is now a graduate student in the School of Freshwater Sciences at the UW-Milwaukee. He states that Milwaukee has always been known to care for their water.

“Milwaukee, even before this, [it] was known for having good quality water and it takes the support of the public and the people to push that and make that a priority to have good quality water that is safe to drink,” Garcia said.