You love your basement. Whether it’s additional storage space, finished living space, or a workbench, basements can add a great deal to your home.
Unfortunately, they can be prone to leaks and even flooding.
Here’s our look into where basements are flooding, along with trends in basement construction, including regional differences. We’ll also dive into the causes.
U.S. Cities with Flooded Basements
Using data from Google Trends on search inquiries for “flooded basement” over the past year, we were able to zero in on the locations of those searches. This data was then sorted by region, metropolitan area, and city. Here’s what we found and their rankings.
Top 15 U.S. Cities with the Worst Flooded Basements
- Toledo, OH
- Cincinnati, OH
- Columbus, OH
- Grand Rapids/Kalamazoo/Battle Creek, MI
- Detroit, MI
- Cleveland/Akron, OH
- Chicago, IL
- South Bend/Elkhart, IN
- Wilkes-Barre/Scranton, PA
- Milwaukee, WI
- Philadelphia, PA
- St. Louis, MO
- Buffalo, NY
- Sioux Falls, SD
- Kansas City, MO
Digging just a little deeper, we found there was a significant increase in inquiries in May. Looking at the NOAA Climate Report for May 2020 we find that Chicago experienced its wettest May on record. This extended across the Midwest and included catastrophic dam failures and flash floods in Michigan.
NOAA also reported the third-wettest May in North Carolina and the fourth-wettest in South Carolina. Plus, Miami reported its wettest May since records have been kept. But few basements flooded there. That’s because there are few if any basements due to soil properties and water level.
Let’s take a look at foundation construction, where basements are popular, and why.
Trends in Foundation ConstructionU.S. Census Bureau new home construction statistics show that in 1971, basements and slab foundations were relatively even, with 36% of new homes with basements and 38% with slabs. Crawl spaces made up the rest with 26%.
Fast forward to 2019, and slab foundations made up 63% of new homes, with basements at 23% and crawl space at 14%. This chart provides perspective on the overall year-by-year changes.
That same data shows in 2019, basements made up 64% of foundation construction in the Northeast, 62% in the Midwest, 24% in the West, and a mere 7% in the South. That would account for why basements aren’t flooding in Miami!
Basement vs. Slab and Crawl Space Foundations
There are a number of advantages of a basement. The big one is additional space. This, in turn, can be converted to finished living space, a workshop, laundry area, and storage. So what’s not to like?
In most cases, the climate, soil type, flooding risks, and whatever other homes in your area are using for foundations drive the ability to use a basement foundation.
In the Northeast and Midwest, the climate includes freezing weather. This means the foundation needs to be below the depth of the frost line. Given that, the foundation will need to be set at a relatively deep level. This also means that there’s not much of a cost difference between a slab with deep footers and a basement. Plus, you have all the added advantages of a basement.
Soil Properties and Water Level
In the South, without concerns from frost, the soil takes on more importance. With sandy soils, homebuilders prefer slab foundations. In addition, sandy soils will allow easy water flow around and into basements, causing flooding. In fact, in many cases, the water table may be too high to allow basement construction.
In other areas of the South, heavy clay is a restricting element. Its expansion and contraction during rainy or drought conditions could literally break up the basement without considerable mitigating efforts. If it did hold together, water could readily flow into spaces between the clay soil and the basement foundation, finding ways to cause leaks and flooding.
As we noted above regarding the weather in May 2020, frequent storms and extreme weather can also be a factor. See our blog post 16 Worst U.S. Cities for Flooding for further insight. In many cases, those cities use slab or crawl space foundations since basements can be problematic.
Of course, if you live in one of those cities (or any other area, for that matter), there are many ways to prepare for and mitigate against basement flooding.
Causes of Basement Flooding
Apart from the severe weather noted above, there are quite a few other causes. Here’s a short list:
Foundation cracks: Some small cracks can occur from natural settling, but cracks in a foundation are critical infrastructure damage. Those cracks need to be addressed to stop leaks before they lead to flooding.
Improper Sealing: Ideally, the basement floor and walls should be sealed both on the outside and inside. This prevents water entry after heavy rain. There is also the challenge of sealing around pipes as they enter the basement.
Plumbing Leaks: Aging, ground shifts, and tree roots can wreak havoc with your plumbing. This causes backups and leaks around the foundation. Over time, it can show up in your basement and/or cause further shifts in the foundation.
Sump Pump Problems: Sump pumps are used to collect water and pump it out of low-lying areas. As they age, or should the power fail, the water can back up and start flooding your basement. It’s absolutely essential to have a battery backup for these systems.
Grade of Slope Around the Home: Ideally, the landscape around your home allows for the rainwater to move away from the foundation. If not, it can collect around your foundation and start seeping into the basement.
Perimeter Drainage System: This type of system is designed to keep water levels below your basement through collection and drainage. If the system gets blocked, water rises and shows up in your basement.
Whether you live in one of the worst cities for basement flooding or not, they are no fun at all. In fact, it’s best to do all you can to avoid that distressing situation.