Water seepage through a cinder block foundation wall in a chicagoland base

Understanding Why Basements Leak

Nasutsa Mabwa

June 23, 2025

Basement leaks are common in Chicagoland due to clay soil and hydrostatic pressure. Learn why basements leak, how to prevent water intrusion, and when to call ServiceMaster Restoration By Simons for expert help.

Why Do Basements Leak in Chicago Homes?

Basements are a standard feature in Chicagoland homes, providing valuable living or storage space. Yet, water intrusion remains one of the most frequent and costly issues homeowners face. In fact, insurance data suggests that 98% of basements experience water damage at some point. Whether it’s a trickle of moisture or significant flooding, understanding why basements leak is key to protecting your home and its foundation.

At ServiceMaster Restoration By Simons, we’ve seen it all. With 40+ years of local water damage restoration expertise, we help Chicago homeowners identify and resolve the root causes of basement leaks before they lead to structural damage or mold growth.

The Main Causes of Basement Leaks

The Clay Bowl Effect

When your home’s foundation was built, contractors excavated a large hole in clay-heavy Chicagoland soil. After the foundation walls and footings were installed, the hole was backfilled with looser soil. This creates what’s called the clay bowl effect.

Why it matters:

Backfill soil is less dense and more absorbent than the untouched surrounding soil.
When it rains, water saturates this looser soil faster, leading to seepage through cracks or porous walls.
Poor grading or downspout issues can worsen the problem, funneling water toward the foundation.

Hydrostatic Pressure

Hydrostatic pressure refers to the force exerted by water on your basement walls. In clay soil, water can accumulate heavily around the foundation after heavy rain, snowmelt, or flooding.

The risks:

Water finds its way through even hairline cracks in basement walls or the cove joint (where floor meets wall).
Persistent pressure can cause walls to bow, crack further, or even fail in extreme cases.

Poor Surface Drainage

If your yard slopes toward your house or gutters are clogged, surface water can pool next to the foundation. Over time, this adds to hydrostatic pressure and increases the likelihood of leaks.

Aging Construction & Settlement

Even well-built basements can develop cracks over time due to normal settling or shifting soil. These cracks offer an easy path for water intrusion, particularly in older Chicagoland homes.

Signs Your Basement May Be Leaking

Damp spots or water stains on walls
Musty odors or visible mold
Efflorescence (white powdery residue)
Peeling paint or warped paneling
Standing water or pooling after storms
Higher indoor humidity levels

If you notice any of these signs, it’s crucial to act quickly before minor moisture becomes a major problem.

How to Prevent Basement Leaks in Chicago

Keep gutters clean and downspouts extended at least 6 feet from your foundation.
Ensure proper grading so the yard slopes away from your home.
Install or maintain sump pumps and battery backups.
Consider French drains or exterior waterproofing during new construction or major renovations.
Seal visible cracks and maintain the integrity of basement windows and window wells.

What to Do If Your Basement Leaks

If you discover water in your basement:

Stay safe. Avoid contact with standing water, especially near electrical outlets.
Document the damage. Take photos and videos for insurance purposes.
Call your insurance company. Ask what’s covered under your policy.
Contact professionals. ServiceMaster Restoration By Simons specializes in water removal, structural drying, and sanitization.

Why Choose ServiceMaster Restoration By Simons

Founded in Chicago in 1929, ServiceMaster is the nation’s oldest restoration brand. Our team at ServiceMaster Restoration By Simons brings over 40 years of local expertise in basement water damage restoration.

✔ IICRC Master Fire & Water Restorer certified
✔ Member of the Restoration Industry Association (RIA)
✔ Trusted by Chicago homeowners for decades
✔ Fast response — 24/7 availability

We handle everything from emergency water removal to structural drying, mold remediation, and packout services. Learn more about our residential water damage services. Call us at 773-376-1110 or click on our website at https://www.servicemaster-restorationbysimons.com

If you’re dealing with a basement leak or want to prevent one, contact the trusted professionals at ServiceMaster Restoration By Simons. We proudly serve Chicago, the North Shore, and DuPage County. Call us at 773-376-1110 or contact us online today.

Nasutsa Mabwa is the CEO and co-owner of ServiceMaster Restoration By Simons, a certified MBE/WBE firm proudly serving Cook, DuPage, and Lake Counties in Illinois. Under her leadership, the company has become one of Chicagoland’s most trusted providers of disaster restoration services, including water and flood damage restoration, fire and smoke damage cleanup, and mold remediation for residential and commercial clients.

A recognized civic and business leader, Nasutsa is a recipient of the 2020 Daily Herald Business Ledger C-Suite Award, a Crain’s Chicago Business 40 Under 40 honoree, and a 2018 ServiceMaster® Achiever Award recipient. She currently serves as a Civic Federation Board Member, an Advisory Board Member, and is the Past President of the Executive Committee for the Evanston Chamber of Commerce. She is a proud member of the WPO - Women's President Organization.

Nasutsa holds IICRC certifications in Water Damage Restoration (WRT) and Fire & Smoke Restoration (FSRT), bringing both strategic leadership and technical expertise to every project.

She is also the co-author of RESTORE: A Complete Guide to Protecting Your Home As Your Most Valuable Asset from Water and Fire Disasters — a practical, accessible book for homeowners based on real-world experience in the restoration industry.

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