BASEMENT FLOODING MITIGATION
 
 

Understanding Chicago's Combined Sewer System​

In the past, water was able to gradually soak into the ground in open areas that are now covered with driveways, streets, parking lots, etc. Today, an estimated 42% of Cook County is impervious surface, meaning water from Chicago's recent record-breaking storms cannot be absorbed. We have removed the natural absorptive capacity of our landscape giving the rainwater nowhere to go. As a result, basement flooding and stormwater management has become a huge issue in Chicago, and for our Chicago bungalows.

During heavy rains, Chicago's 100 year old combined sewer system may reach capacity resulting in backup. In a combined sewer system, sanitary sewage and stormwater drain into the same pipes. Homes, businesses and street drains are connected to the local sewers, which are owned and maintained by municipalities. Local sewers flow by gravity into the Metropolitan Reclamation District of Greater Chicago (MWRD) intercepting sewers, which then convey the flow to MWRD water reclamation plants for treatment. 

The City of Chicago certainly has a responsibility to help mitigate the impact of storm water, but as homeowners, we play a large role in managing the stormwater that falls onto our property. We are all responsible for water management in Chicago, and collectively we can make a difference.

The information below was provided by Ryan Wilson of Elevate Energy in partnership with CBA's Basement Flooding seminars, thanks to a grant from the Illinois Department of Natural Resources (IDNR). Use this as a guide to learn what problems to look for, where and when to look for them, low cost improvements, plus helpful hints and next steps.

 

Identifying Flood Risks at Your Property

Before you can manage water on your property, it's important to identify which type of flooding you are dealing with.

 

There are 3 types of flooding

  1. Water & Sewer Backup

  2. Foundation Seepage

  3. Yard Flooding

Image Courtesy of: Institute for Catastrophic Loss Reduction

Use the symbols below to guide you on identifying and improving flood risks at your property:

               Do-It-Yourself                              Hire a Contractor

Backup through Drains, Sump Pumps, Sinks, Tubs & Toilets
What to look for

  • Standing water (clear, dirty, sewage)

  • Stains on walls & floors

  • Sediment near drains, open sump pumps

Where

  • Near floor drains, open sump pumps

  • Basement sinks, tubs , toilets

When

  • During rain 

  • After rain 

Hint: Check your basement during and after rains. Standing water after rain stops
could mean blocked pipes.

Next Step: Hire a licensed plumber to televise building sewer

 
Seepage at Cracked or Porous Foundation​
What to look for

  • Water coming from walls

  • Cracks in exterior walls

Where

  • Foundation walls in basement

  • Seam of wall and floor (cove joint)

  • Pipe penetrations at foundations

When

  • During rain 

  • After rain 

  • Dry weather

Hint: Look for water stains on the floor, peeling paint, or powder-covered brick.

Next Step: Run a garden hose for 30 min to an hour to test cracks;
consult foundation repair contractor

Leaking Window Wells or Doors​
What to look for

  • Gaps near basement windows & doors

  • Damage to door seals & window weather stripping

  • Water or water damage at window sills

Where

  • Basement windows or doors

When

  • During rain 

  • After rain 

Hint: Window or stairwells without drains are common sources

Next Step: Inspect condition of doors and windows

Downspout Discharge Near Foundation​

What to look for

  • Broken or obstructed downspouts

  • Disconnected or missing downspouts

Where

  • Exterior perimeter of home

When

  • During rain 

Hint: Bungalows often have 2 or more downspouts to drain the many roof areas.

Next Step: Inspect downspouts in dry weather, and again during rain.

Low Points near Foundation​
What to look for

  • Standing water during and after rain

  • Perennially wet soils

Where

  • Near foundation

When

  • During rain

  • After rain

  • Dry weather

Hint: Soils around buildings settle over time; downspout discharge can scour
soil and create low points

Next Step: Inspect foundation in dry weather, and again during rain.

Low Points in Yard
What to look for

  • Standing water during and after rain

  • Perennially wet soils

Where

  • Yard

When

  • During rain

  • After rain

  • Dry weather

Hint: Look for places that are often wet or where grass doesn't grow.

Next Step: Inspect yard in dry weather, and again during rain.

Low or No-Cost Improvements

Clean Gutters
Why

  • Water overflowing gutters

  • Clogged or obstructed building sewers

What to do

  • Clear gutters

  • Install gutter guards

Considerations

Disconnect Downspout from Building Sewer
Why

  • Water backup

  • Downspouts are connected to building sewer

What to do

  • Cut downspout; remove connection from sewer

  • Extend >10' from foundation

Considerations

  • Capture water on-site

  • Don't send water to neighbors

Extend Downspout to Yard
Why

  • Downspout discharges near foundation

What to do

  • Extend discharge 10' from foundation

Considerations

  • Capture water on-site

  • Overflow route to right-of-way

  • Don't send water to neighbors

Caulk Joints & Cracks near Foundation
Why

  • Block point of entry for water​

What to do

  • Clean existing joints or cracks

  • Caulk cracks; use foam backing

Considerations

  • Weather-resistant materials

  • Other points of entry

  • Foundation cracks may require contractor

  • Don't send water to neighbors

Slope Yard away from Foundation​
Why

  • Direct water away from foundation

What to do

  • Grade yard to drain away from foundation

Considerations

  • Add or remove soil

  • Soil with high clay content

  • Perennial plants

  • Don't send water to neighbors

Install a Rain Garden​
Why

  • Capture water from downspout or paved surfaces

  • Improve drainage in yard

What to do

Considerations

  • Storage volume

  • Proximity to foundation

  • Infiltration capacity of soils

  • Don't send water to neighbors

Install Rain Barrel(s) or Cistern

Why

  • Reuse water for irrigation

What to do

  • Disconnect downspout

  • Attach a rain barrel

  • Ensure necessary overflow route

Considerations

  • Size to serve source area(s)

  • Discharge >10' from foundation

  • Don't send water to neighbors​

Install a Standpipe
Why

  • Stop water from entering basement

What to do

  • Install secure pipe connection to all floor drains

Considerations

  • Multiple drain locations

  • Obstruction of walkways

  • Height of pipe

  • Condition of seal

Hire Trusted Contractors​
  • Foundation crack repair

  • Sewer rodding & televising

  • Backwater valve

  • Interior drain tile

  • Sump pump or ejector pumps

  • Overhead sewer

 

Flooding Resources