Case Study: Drying a Flooded Basement Using Pumps, Carpet Dryers, and Dehumidifiers

Let’s face it – a flooded basement is a homeowner’s worst nightmare. You wake up one morning, head downstairs and see water covering your basement floor. Your stomach drops. The good news is that if you have the proper equipment and a plan of attack, you can dry out your flooded basement quickly and minimize long-term damage. This case study breaks down how to do it…

The Backstory

Meet "James." He lives in a neighborhood where torrential spring rains happen frequently. During one particularly bad thunderstorm, water seeped in through his basement walls and floor drain. He went to sleep about nine pm that night with almost two inches of water covering his entire 600-square-foot basement. Come morning, the carpet was soaked through, the walls were damp and the basement smelled musty.

James knew he needed to dry things out quickly. Mold can begin growing in as little as 24-48 hours after standing water is present. Due to that fact, James sprang into action and gathered his equipment:

Step 1 - Remove Standing Water With A Pump

James knew the first thing he needed to do was remove all of the standing water. You can’t properly dry a room if you let water sit on the floor. Thankfully, it doesn’t take long to pump water out with the proper tool. James used a submersible sump pump to quickly remove the bulk of the water.

These pumps simply sit in the water and pump them out through a discharge hose. James hooked his pump’s discharge hose up to a window in his basement and let the water drain out into his yard. After about two hours of pumping, most of the water was gone.

Renting a submersible pump from your local hardware store costs about $40-$60 per day. It’s well worth the money. For small areas or hard-to-pump water, try using a wet-dry vacuum.

James rigged up his shop vac to help suck-up any leftover water from corners and along the baseboards that the submersible pump couldn’t reach.

Overall, taking the time to remove the standing water first made the drying process go much faster. If you skip this step you’ll just be wasting your time with the rest of these steps.

Step 2 - Pull Up The Wet Carpet

James found himself staring down at a giant SpongeBob when the standing water was gone. Wet carpet is one of the worst things to deal with when trying to dry out a flooded basement. It absorbs moisture like a sponge and attracts mold and mildew.

Using a pair of gloves, James pulled the carpet away from the wall on all sides. He cut the carpet into several manageable strips using a utility knife. He also pulled-up the carpet padding underneath, which was completely soaked. Carpet padding nearly always fails when wet and should be thrown away.

Although it can be difficult, don’t let attachment to your carpet keep you from ripping it up. Leaving damp carpet in place will only prolong the drying process and leave you more susceptible to mold growth.

Step 3 - Bring In The Carpet Dryers And Air Movers

After removing the carpet and padding, James next brought in two heavy-duty air movers. Also known as carpet dryers or "blower fans," these are not your average household fan. These powerful machines move large volumes of air across wet surfaces at a low angle to greatly increase evaporation rates.

One air mover was pointed at the exposed concrete floor while the other was pointed at the walls. Fast-moving air draws moisture out of surfaces and into the air of the room.

Within hours you could visibly see the floor drying before your eyes. However, air movers are most effective when used in conjunction with dehumidifiers. This brings us to our next step. Air movers can usually be rented from your local equipment rental store or water damage restoration supplier. Rental costs are usually between $25-$50 per machine per day.

Step 4 - Run The Dehumidifiers

This is where the serious drying begins. Although air movers help move moisture out of carpets and walls, they don’t automatically remove moisture from the air. You must have a dehumidifier to capture water vapor and keep it from resettling back onto your floors and walls.

James rented two commercial-grade dehumidifiers and plugged them in. He opted for units that were rated highly for moisture output (at least 70 pints per day). Sometimes, traditional home dehumidifiers are not powerful enough for flooded spaces. Because of this, it’s usually best to rent a commercial unit if you’re in a bind.

It’s important to continuously drain your dehumidifiers when drying out a large space. Make sure the drain hose is directed to either a floor drain or outside. You don’t want to constantly be emptying buckets! Make sure your windows and doors are closed to keep outdoor humidity from entering and prolonging the drying process.

The basement took about 72 hours to dry completely. James monitored progress by using a hygrometer to track relative humidity. 50% or less is ideal for preventing mold growth.

Step 5 - Monitor And Inspect

The final step in drying out your basement is to consistently monitor the progress. Pull out your moisture meter every morning and night to check on things. These inexpensive tools allow you to literally measure how much moisture is in your walls and floors.

If you regularly check in with the drying process, you’ll be able to catch things like above. James found a section of damp drywall that wasn’t drying quickly enough. He used a drywall saw to cut the bottom six inches out to allow for airflow from behind.

Needless to say, James' basement was dry in 5 days, the moisture readings were normal and there was no mold.

Frequently Asked Questions (FAQ)James cut his drywall—do I always have to do that?

Not always, but it's the safest bet. Drywall acts like a wick; it sucks water up. If the water was more than an inch deep or sat for more than a few hours, the insulation behind the wall is likely soaked. If you don't cut a "flood cut" (usually 12-24 inches up), that wet insulation will stay damp for weeks, causing mold to grow where you can't see it.

Why did James use a "Submersible Pump" instead of just a wet-vac?

Efficiency. A standard shop-vac holds about 10–15 gallons. Two inches of water in a 600 sq. ft. basement is roughly 750 gallons. James would have had to empty that vacuum 60 times! A submersible pump does the heavy lifting automatically, leaving the shop-vac for the final "detailing" in the corners.

What's the deal with "LGR" dehumidifiers James used?

Standard home dehumidifiers stop being effective once the room gets to a certain dryness. LGR (Low Grain Refrigerant) units are the "special forces" of drying. They can keep pulling water out of the air even when the humidity is very low. This creates a "vapor pressure" imbalance that literally sucks water out of the wooden wall studs and concrete floor.

James threw away his carpet padding but kept the carpet. Is that okay?

In "Category 1" (clean pipe burst) water, you can often save the carpet if you clean and dry it quickly. However, carpet padding is like a giant sponge made of recycled foam; you can almost never get it dry or clean enough to prevent smells. It’s cheap to replace, so ripping it out is the smart move. If the water was from a sewage backup, everything porous (carpet and pad) must go.

How do I know if I’ve "finished" the job?

Don't trust your nose or your hands. Use a moisture meter. Take a reading of a wall on the second floor of your house—that is your "Dry Standard." Keep your fans and dehumidifiers running in the basement until the basement walls and floors match that number. Usually, this takes between 3 and 5 days.

Final Words

Drying out your flooded basement is no easy task, but it can be done with the proper equipment and know-how. Time is of the essence when dealing with water damage. The sooner you start the drying process, the better off you’ll be. Follow this guide and you’ve got this!

Uneeb Khan is the founder of Techager and has over 6 years of experience in tech writing and troubleshooting. He loves converting complex technical topics into guides that everyone can understand.