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Metropolitan Water Reclamation District of Greater Chicago

Riverside-Brookfield Landmark: Riverside residents who are signed up to receive emails from the village may have noticed one subject line that occasionally reappears in their inboxes: “MWRD Releases Overflow Action Alert.” At first glance, this simple phrase could cause confusion or alarm. Is the Des Plaines River flooding into town? What about your basement? Does emergency action need to be taken?

The answer to these questions is no — at least, not yet. Over the past few weeks, the MWRD, short for the Metropolitan Water Reclamation District of Greater Chicago, has issued two overflow action alerts, one March 14 and the other April 1. Both days brought heavy rain to the Chicagoland area, and on both days, Riverside reposted the alerts to the village’s website and sent them out via email.

Whether you’ve never heard of an overflow action alert in your life or you’ve seen them on Riverside’s website from time to time, read on to learn about why these alerts are important and how you can make a difference in water conservation efforts by following the MWRD’s recommendations. Anyone can sign up to receive them directly from the MWRD through text messages on the organization’s website.

What are overflow action alerts?

When the MWRD issues overflow action alerts, they are not indicative of flooding or any other emergency situation. Instead, these alerts are intended to serve as reminders to residents of the Chicagoland area that whenever there is heavy rain, they should try to conserve as much water as possible before, during and after the storm.

In the alerts, the MWRD advises against using water in everyday ways, like taking showers, flushing toilets, running the dishwasher or doing laundry, at least until the heavy rain event has passed.

The alerts also include a brief explanation of why you shouldn’t use water during rainstorms: “Flooding and sewer backups can happen for a variety of reasons, ranging from conveyance of water flow in local pipes, the groundwater table, undersized drainage designs and roof loads, and sump pumps attached to house lines.”

Of course, Riversiders are no strangers to floods. The village’s proximity to the Des Plaines River puts it at risk of flooding when heavy rains or other phenomena cause the river to rise. Village officials have been working toward constructing a floodwall east of the river since 2013, when the river reached its highest recorded crest and caused extensive flooding in town. Flood watches in Riverside have been issued as recently as January.

But wait… what does that mean?

In its brevity, this explanation may not satisfy every reader. Flooding and sewer backups do happen for many reasons, an important one being a lack of separate infrastructure for rainwater.

“In Chicago and older suburbs, rainwater shares the same set of pipes as the water that flows down the drains of our homes. The flow from your toilets, bathtubs, laundry machines, dishwashers and kitchen sink all funnels down the same system as a rain [event],” said Allison Fore, the MWRD’s public and intergovernmental affairs officer, in an email. “When too much water enters sewers too quickly, as in the case of a heavy rainstorm, the sewers can back up into streets and basements.”

Fore added that most sewers in Chicagoland carry both rainwater and sanitary sewage from people’s homes.

“These combined sewers were built before wastewater treatment technology existed and were originally designed to flow straight into waterways,” she said.

Why should you listen to overflow action alerts?

If you’ve read this far and thought to yourself, “I don’t need to listen to these alerts,” you’re probably not alone. While no one is required to make efforts toward conserving water during rainstorms, every bit counts — and the MWRD agrees.

“One person may think [their] actions are not important. This is not the case. Water conservation can not only lead to a clean and thriving water environment, but it can also help us build capacity in our sewer systems, treatment plants and other infrastructure to collect and manage more water,” Fore said. “The more our neighbors join us in conserving water, the more room we have to manage the fierce rainstorm events we have experienced in recent years.”

According to the United States Environmental Protection Agency, each American uses 82 gallons of water per day on average; across Cook County’s recorded 5.28 million inhabitants as of the 2020 U.S. Census, that adds up to about 430 million gallons of water entering sewers each day within the MWRD’s service area, which includes most of the county.

“Every little bit of conservation can help reduce the overall amount of water in the system,” Fore said.

Why and how does the MWRD issue overflow action alerts?

The MWRD started issuing overflow action alerts in 2016 as part of a partnership with Friends of the Chicago River, a nonprofit dedicated to improving the Chicago River system’s health, Fore said.

She also said the MWRD was inspired by ozone action days, a similar program where municipalities across the country can issue alerts to residents on days where the air quality index falls within the unhealthy range.

On its website, the MWRD says it issues overflow action alerts whenever “heavy rains are forecast.” Broadly speaking, this is true, but the organization’s actual criteria is a bit more specific.

“We issue overflow action alerts based on a combination of the rain totals anticipated in our forecasts and an analysis of the amount of capacity currently in our [Tunnel and Reservoir Plan] system and other infrastructure,” Fore said. “The MWRD does not predict [combined sewer overflow] events but has various triggers set in place to inform us of the likelihood of a sewer overflow based on storage capacity, forecasts and other elements.”

The organization describes its Tunnel and Reservoir Plan as “a system of deep, large diameter tunnels and vast reservoirs … designed to reduce flooding, improve water quality in Chicago area waterways and protect Lake Michigan from pollution caused by sewer overflows.”

The MWRD does not issue alerts for specific regions within its service area, which covers nearly 900 square miles, Fore said.

What else does the MWRD do?

Aside from issuing overflow action alerts, the MWRD is responsible for a broad range of projects and goals related to managing Chicagoland’s water.

According to its mission statement, the MWRD aims to “protect the health and safety of the public in its service area, protect the quality of the water supply source (Lake Michigan), improve the quality of water in watercourses in its service area, protect businesses and homes from flood damages, and manage water as a vital resource for its service area.”

The MWRD manages seven water reclamation plants across Cook County, which together treat 1.3 billion gallons of wastewater each day on average. According to the most recent overflow action alert, “that number can soar above 2 billion with intensive rainstorms.”

For a complete explanation of the MWRD’s responsibilities and goals, visit its website.

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Established in 1889, the Metropolitan Water Reclamation District of Greater Chicago (MWRD) is an award-winning, special purpose government agency responsible for wastewater treatment and stormwater management in Cook County, Illinois.


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