Flood Control in Lemont and Homer Glen, IL

Why Two Communities at the Confluence of the Chicago Area Waterway System Face Some of the Most Complex Flood Risks in the Southwest Suburban Corridor

 

Most Chicago suburbs deal with one watershed, one sewer system, and one set of flooding mechanisms. Lemont and Homer Glen deal with a more complicated picture — and it starts with geography that almost no other community in the metropolitan area shares.

 

Lemont sits at the convergence point of two of the most significant engineered waterways in North American history. The MWRD’s Cal-Sag Channel Watershed documentation confirms it directly: the Cal-Sag Channel — constructed between 1911 and 1922, connecting the Little Calumet River to the Chicago Sanitary and Ship Canal — flows to the Chicago Sanitary and Ship Canal in Lemont. The MWRD controls the flow and water level in the Chicago Area Waterway System using control structures at the southernmost point of the system: the Lockport Powerhouse, located just downstream of Lemont.

 

This is not an abstract geographic fact. The entire drainage network of Chicago and its suburbs — the combined storm and sanitary flow from millions of residents — ultimately moves through the waterway corridor that runs directly through and adjacent to Lemont. The Des Plaines River runs alongside this same corridor. The Illinois and Michigan Canal historic waterway parallels it. And just south of this complex, Homer Glen sits in the Des Plaines River valley on the same glacially deposited terrain that the IDNR’s history of Illinois flood control describes as historically swampy — terrain where even modern storm sewer systems work against the area’s natural tendency to hold water.

 

Presidential Disaster Declarations have been issued for both Cook County and Will County — the two counties that divide Lemont and Homer Glen between them — for severe weather events in July 2024. That’s a formal federal acknowledgment of the flooding risk in this specific corridor.

 

This guide covers the complete flood control picture for both communities — what’s actually driving flooding in Lemont and Homer Glen, why the solutions are different here than in Chicago’s combined sewer communities, and what every homeowner in this corridor needs to protect their home before the next major event.

 

The Des Plaines River — A Real, Documented Flood Risk With Specific Numbers

 

The National Oceanic and Atmospheric Administration maintains an active, real-time flood stage gauge specifically for the Des Plaines River near Lemont. This is not a theoretical risk — it’s a monitored waterway with documented flood events.

 

The numbers matter: flood stage for the Des Plaines River at Lemont is 10 feet. In May 2020, after 4 inches of rain fell across the area, the Des Plaines River near Lemont broke its flood record — reaching 13.26 feet, indicating moderate flooding, and shattering the previous record of 12.6 feet. The river had risen from approximately 7 feet to 13.26 feet over the course of a single weekend. Properties in Lemont’s Des Plaines River floodplain experienced direct flood exposure during that event.

 

The National Weather Service’s documented history of flooding along the Des Plaines River corridor includes multiple significant events where hundreds of homes along the Des Plaines River were flooded — in some cases with basements flooded to the ceiling. The Des Plaines River at Lemont is not an occasional nuisance. It is an active, monitored, record-breaking flood risk with a real history of significant residential damage.

 

What this means for Lemont homeowners near the river: FEMA flood zone status matters here. Use FEMA’s Flood Map Service Center with your specific address to confirm whether your property is in a Special Flood Hazard Area. Properties in designated Special Flood Hazard Areas with federally backed mortgages are required to carry flood insurance — and even for properties not technically in the designated flood zone, the river’s documented ability to break historical records during major rain events makes flood insurance worth discussing with your agent.

 

The Dual-County Situation — Two Counties, Two Different Assistance Programs

 

Both Lemont and Homer Glen span the boundary between Cook County and Will County — and which county your property falls in determines which financial assistance programs apply, which sewer infrastructure serves you, and which agency to call for drainage concerns.

 

Lemont’s Cook and Will County split: The Village of Lemont spans both Cook and Will Counties. Properties in the Cook County portion of Lemont have access to Cook County’s active flood control assistance programs, including the Sewer Backup Prevention Program (up to $5,000 for qualifying installations, permit fees waived) and the 2025 CDBG-DR federal recovery funding approved in response to the 2023 and 2024 severe weather events. Properties in the Will County portion of Lemont access Will County resources and the Lemont Sanitary District for sewer service.

 

Homer Glen’s Cook and Will County split: As we cover in our complete Homer Glen plumbing guide, Homer Glen similarly spans both counties with Illinois American Water serving the majority of Homer Glen homes through infrastructure built in the early 1970s. The county your specific parcel falls in determines which assistance programs apply.

 

Before any flood control installation in either community: Confirm your county, then contact the appropriate county stormwater management program to ask about available funding. For Cook County-side properties, contact Cook County at (708) 865-4720. For Will County-side properties, contact Will County Land Use at (815) 727-8672.

 

Why Flooding Here Is Different From Chicago’s Combined Sewer Communities

 

This is the most important distinction for Lemont and Homer Glen homeowners — and getting it wrong leads directly to installing the wrong flood control system.

 

Chicago and most inner-ring Cook County suburbs have combined sewer systems where stormwater and sanitary waste share the same underground pipes. During major rain events, those systems surcharge — the combined pressure reverses through residential laterals and produces sewage-odored basement floor drain backup. The solution for that mechanism is a backwater valve or overhead sewer conversion.

 

Lemont and Homer Glen have separate sewer systems. Stormwater and sanitary waste are in completely separate underground infrastructure. The combined sewer surcharge mechanism — the primary flooding driver in Berwyn, Cicero, and Chicago’s inner ring — is largely absent here.

 

What this means in practice: If your Lemont or Homer Glen basement floods and the water has no sewage odor, you are almost certainly NOT dealing with combined sewer surcharge backup. You’re dealing with one or more of the mechanisms that drive flooding in this specific corridor:

 

• Des Plaines River flood plain overflow — direct overland flooding for properties near the river

 

• Groundwater intrusion from the Des Plaines River valley’s high water table — the same “historically swampy” geology that fills Spring Creek, Long Run Creek, and Marley Creek with water during major events pushes upward against basement foundations throughout this corridor

 

• Stormwater accumulation on clay-heavy soil — flat sections of Lemont and Homer Glen with clay-heavy glacially deposited soil accumulate surface water faster than the ground absorbs it

 

• Tributary creek overflow — Spring Creek, Long Run Creek, and Marley Creek all drain southwest through this corridor into the Lower Des Plaines River, and their overflow during major events affects properties in their immediate corridors

 

The Four Flood Control Solutions for Lemont and Homer Glen

 

Solution 1: Sump Pump With Battery Backup — The Primary Defense in This Corridor

 

For the vast majority of Lemont and Homer Glen homeowners whose flooding is groundwater-driven rather than sewer-surcharge-driven, the sump pump is the first and most important flood control installation available. In the Des Plaines River valley’s high water table geology, a sump pump isn’t optional maintenance — it is the primary mechanism that keeps basements dry during the major rain events that repeatedly push the Des Plaines River above flood stage.

 

Our sump pump services cover both communities with same-day and 24/7 emergency response. For Lemont and Homer Glen specifically, the battery backup component is non-negotiable: the storms that produce the worst Des Plaines River flooding events — the kind that broke the flood record at Lemont in May 2020 — are precisely the storms most likely to knock out power. A sump pump without battery backup fails during the exact event it was needed most.

 

If your home in either community was built in the 1980s or 1990s, your original sump pump may be 30 to 40 years old — well past its service life. Assessment and replacement before the next storm season is the highest-priority action available for most homes in this corridor.

 

Solution 2: Backwater Valve — For Cook County-Side Lemont Homes on Combined Sewer

 

While Lemont and Homer Glen primarily have separate sewer systems, specific sections of Lemont — particularly in the older, more established neighborhoods near the village center — may be served by older combined sewer infrastructure. For any Lemont homeowner whose basement flooding involves sewage odor and correlates specifically with peak storm intensity, the combined sewer surcharge mechanism is worth investigating.

 

If camera inspection of your private lateral confirms a combined sewer connection and sewer surcharge backup is contributing to your flooding, a backwater valve physically prevents that surcharge from entering your home’s drain system. Our sewer backflow prevention services cover backwater valve installation throughout Lemont with all required permits included.

 

Contact the Lemont Sanitary District at (630) 257-2611 to confirm which sewer system serves your specific address before investing in any flood control installation.

 

Solution 3: Overhead Sewer Conversion — Permanent Protection for Recurring Sewer Backup

 

For any Lemont homeowner with a confirmed combined sewer connection who has experienced repeated severe sewer backup events — or who wants permanent structural protection rather than mechanical protection from a valve — an overhead sewer conversion eliminates the below-grade connection to the combined sewer entirely. After an overhead conversion, combined sewer backup is physically impossible regardless of storm intensity.

 

Our overhead sewer services handle the full conversion process in Lemont with all required permits. For Cook County-side Lemont properties, the Cook County Sewer Backup Prevention Program may provide up to $5,000 toward qualifying overhead sewer installations — call Cook County before signing any contract.

 

Solution 4: French Drain and Yard Drainage — For Surface and Lateral Groundwater

 

For Lemont and Homer Glen properties where the flooding source is surface accumulation or lateral groundwater movement rather than the water table rising straight up through the slab, a French drain system intercepts that flow before it reaches the foundation. In the Des Plaines River valley’s clay-heavy soil, surface water that falls faster than the ground can absorb it accumulates against foundation walls — exactly what a properly installed French drain is designed to intercept and redirect.

 

Our French drain installation service covers both communities with designs that account for the specific clay-heavy glacially deposited soil conditions in the Des Plaines River corridor. Discharge routing matters particularly near the river corridor — any drainage installation in Lemont’s flood plain sections may require coordination with the Village of Lemont’s Engineering Department to confirm the appropriate discharge point.

 

Lemont’s Unique Position in the Chicago Area Waterway System

 

The Cal-Sag Channel was constructed between 1911 and 1922, connecting the Little Calumet River to the Chicago Sanitary and Ship Canal specifically in Lemont. This means the entire western portion of the Chicago Area Waterway System — carrying drainage from hundreds of square miles of developed Cook County — flows through and terminates in Lemont’s corridor. The MWRD’s control structure at the Lockport Powerhouse manages the flow at the southernmost point of this system, directly adjacent to the Lemont/Lockport area.

 

This has two specific implications for Lemont homeowners:

 

The Cal-Sag Channel watershed itself is under stormwater pressure during major events. The MWRD manages three regional reservoirs in the Cal-Sag watershed — the Bedford Park Reservoir (188 acre-feet) and Melvina Ditch Reservoir in Burbank (165 acre-feet) — specifically to provide 377 acre-feet of stormwater detention capacity. When those regional facilities are managing peak flows, the pressure on the entire watershed network — including the stormwater and drainage systems serving Lemont — is at its maximum.

 

MWRD stormwater projects are active in the Cal-Sag corridor. The MWRD has more than 240 active and complete stormwater projects throughout Cook County. Several of these address the Calumet-Sag Channel drainage area that includes portions of the Lemont corridor. The public infrastructure investment is real and ongoing — and the same principle that applies throughout this article library applies here: public investment in the drainage network improves the system that private lot drainage connects to, but it doesn’t install anything on your property or inside your home.

 

Homer Glen’s Specific Flood Control Picture

 

Homer Glen’s flooding profile is simpler than Lemont’s in one important respect: no portion of Homer Glen sits at the convergence of major waterways the way Lemont does. Homer Glen’s flooding is almost entirely groundwater-driven — the water table rising in Will County’s clay-heavy soil during sustained rain events and spring snowmelt, pushing upward against basement foundations throughout the community.

 

The natural spring connection: As we covered in our complete Homer Glen plumbing guide, Homer Glen’s water infrastructure is operated by Illinois American Water through three wastewater reclamation facilities built in the early 1970s. But the flooding picture is separate from the utility situation: Homer Glen’s Will County terrain, with its proximity to the Des Plaines River watershed and its clay-heavy soil, creates the groundwater pressure conditions that drive basement flooding in the community. A properly sized sump pump with battery backup — installed and maintained correctly — is the cornerstone of flood protection for the overwhelming majority of Homer Glen homes.

 

For the 21% of Homer Glen homes on private septic: A high water table during major rain events doesn’t just create basement flooding risk — it reduces drainfield absorption capacity. If you’re in Homer Glen on a private septic system and you experience slow drains or backup during sustained wet periods, the source may be temporary drainfield saturation from the high water table rather than a failing septic system. Contact the Will County Health Department at (630) 679-7030 for guidance on this specific condition.

 

The Presidential Disaster Declarations — What They Tell You

 

The July 2024 severe weather events that produced Presidential Disaster Declarations for both Cook and Will Counties weren’t isolated anomalies. The National Weather Service’s Scott Lincoln, senior service hydrologist for the NWS Chicago forecast office, stated that storms like those of July 2023 — severe enough to generate federally declared flood disasters — are no longer once-in-a-decade events. This decade alone has seen three extreme rainfall events — the highest known number since 1950.

 

For Lemont and Homer Glen homeowners, this pattern means one thing: flood events that were historically rare enough to be dismissed as exceptional are becoming regular enough to plan around. The sump pump that was “fine for the weather we usually get” may not be adequate for the weather this region is now generating. The finished basement that has never flooded may not have been tested by a genuine major event yet.

 

The appropriate response is the same one we recommend throughout this corridor: proactive assessment, properly sized equipment, battery backup on every sump system, and where flooding has already occurred, identification and installation of the right flood control solution for the specific mechanism driving that flooding.

 

What Lemont and Homer Glen Homeowners Should Do Right Now

 

Confirm your county first. Cook County or Will County — your tax bill confirms it. The county determines which financial assistance programs are available and which agency to call for drainage concerns.

 

If you’re in Cook County-side Lemont: Contact Cook County about the Sewer Backup Prevention Program before signing any flood control contract. Up to $5,000, permit fees waived.

 

If your home has flooded and the water had sewage odor: Contact the Lemont Sanitary District at (630) 257-2611 to confirm your sewer system type. If you’re on a combined sewer, backwater valve assessment is the next step.

 

If your home has flooded and the water had no sewage odor: Groundwater. Sump pump assessment and upgrade — battery backup if not present — is the priority.

 

If your sump pump is more than 7 years old: Assessment before next storm season. Replace it and add battery backup. Do not wait for failure.

 

If your Lemont property is near the Des Plaines River corridor: Confirm your FEMA flood zone status and ensure adequate flood insurance coverage.

 

For Homer Glen homes on septic experiencing slow drains during wet periods: Call Will County Health at (630) 679-7030 to distinguish temporary drainfield saturation from actual septic failure before calling a plumber.

 

Frequently Asked Questions: Flood Control in Lemont and Homer Glen

 

My flooding has no sewage odor. Can a backwater valve still help?
Almost certainly not for your specific flooding type. Backwater valves stop combined sewer surcharge backup — a mechanism where sewage-odored water reverses through a combined sewer lateral during peak storm events. Flooding without sewage odor in Lemont or Homer Glen is almost always groundwater from a rising water table — which the sump pump addresses, not the backwater valve. Installing a backwater valve for a groundwater flooding problem is one of the most common and expensive flood control mistakes we see. For the complete diagnostic framework, see our complete guide to flood control systems that actually work.

 

The Des Plaines River flooded near my Lemont property. Does that mean I need flood insurance?
Potentially, depending on your specific parcel’s FEMA flood zone designation. Properties in designated Special Flood Hazard Areas with federally backed mortgages are required to carry flood insurance, but any property near the Des Plaines River corridor may face meaningful flood risk regardless of its specific zone designation. Use FEMA’s Flood Map Service Center with your address, and discuss your specific risk profile with your insurance agent.

 

I’m in Homer Glen and my basement floods every spring during snowmelt. Is this normal?
It’s common — but it’s not inevitable. Homer Glen’s Will County terrain and proximity to the Des Plaines River watershed create the groundwater conditions that produce spring flooding in many homes. A properly sized sump pump with battery backup manages this condition actively rather than allowing the spring water table rise to enter the basement. If your current sump pump is running continuously during spring snowmelt and still losing ground, the pump may be undersized for your property’s specific infiltration rate, or it may be aging to the point where its performance has degraded below its original rated capacity.

 

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