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
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Water & Sewer Backup
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Foundation Seepage
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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
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Standing water (clear, dirty, sewage)
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Stains on walls & floors
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Sediment near drains, open sump pumps
Where
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Near floor drains, open sump pumps
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Basement sinks, tubs , toilets
When
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During rain
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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
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Water coming from walls
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Cracks in exterior walls
Where
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Foundation walls in basement
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Seam of wall and floor (cove joint)
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Pipe penetrations at foundations
When
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During rain
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After rain
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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
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Gaps near basement windows & doors
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Damage to door seals & window weather stripping
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Water or water damage at window sills
Where
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Basement windows or doors
When
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During rain
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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
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Broken or obstructed downspouts
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Disconnected or missing downspouts
Where
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Exterior perimeter of home
When
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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
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Standing water during and after rain
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Perennially wet soils
Where
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Near foundation
When
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During rain
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After rain
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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
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Perennially wet soils
Where
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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
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Water overflowing gutters
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Clogged or obstructed building sewers
What to do
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Clear gutters
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Install gutter guards
Considerations
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Take necessary safety precautions
Disconnect Downspout from Building Sewer
Why
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Water backup
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Downspouts are connected to building sewer
What to do
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Cut downspout; remove connection from sewer
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Extend >10' from foundation
Considerations
-
Capture water on-site
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Don't send water to neighbors
Extend Downspout to Yard
Why
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Downspout discharges near foundation
What to do
-
Extend discharge 10' from foundation
Considerations
-
Capture water on-site
-
Overflow route to right-of-way
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Don't send water to neighbors
Caulk Joints & Cracks near Foundation
Why
-
Block point of entry for water
What to do
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Clean existing joints or cracks
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Caulk cracks; use foam backing
Considerations
-
Weather-resistant materials
-
Other points of entry
-
Foundation cracks may require contractor
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Don't send water to neighbors
Slope Yard away from Foundation
Why
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Direct water away from foundation
What to do
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Grade yard to drain away from foundation
Considerations
-
Add or remove soil
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Soil with high clay content
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Perennial plants
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Don't send water to neighbors
Install a Rain Garden
Why
-
Capture water from downspout or paved surfaces
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Improve drainage in yard
What to do
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Size garden appropriately
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Plant perennials
Considerations
-
Storage volume
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Proximity to foundation
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Infiltration capacity of soils
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Don't send water to neighbors
Install Rain Barrel(s) or Cistern
Why
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Reuse water for irrigation
What to do
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Disconnect downspout
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Attach a rain barrel
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Ensure necessary overflow route
Considerations
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Size to serve source area(s)
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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
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Obstruction of walkways
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Height of pipe
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Condition of seal
Hire Trusted Contractors
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Foundation crack repair
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Sewer rodding & televising
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Backwater valve
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Interior drain tile
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Sump pump or ejector pumps
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Overhead sewer
Flooding Resources
Disconnected downspout near foundation
Low point near foundation
Low point near foundation
Low point in yard
Clean gutters
Image Source: mishaandmia.blogspot.com
Extend downspout to yard
Backer rod
Plant perennials