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How to Clean a Flooded Basement: A Step-by-Step Guide

Flooded Basement Cleanup

Once the source of a flooded basement has been found and taken care of you will want to start the cleanup as soon as possible. However, before entering your basement you will need to ensure that it is safe to do so. There are many hazards that come with flooded basement cleanup, including electric shock, gas leaks, raw sewage and structural damage. 

Once it is safe to enter your basement you can begin the cleanup process.

Step 1: Pump the Water Out

There are water removal services available for hire, however, if there is a widespread flooding problem in your area they might not be able to get to your home for a few days. If you’re up to the task it might be a good idea to pump the water out yourself to ensure it’s removed as soon as possible. The necessary equipment isn’t overly expensive and is often available for temporary use from a construction rental store.

Floods that are less than an inch deep and cover a small amount of space can likely be dealt with by using a wet/dry vacuum. They work like a regular vacuum, sucking water into a tank that generally holds about four or five gallons of water. Just keep in mind that you will have to empty the tank regularly so don’t take on a flood that’s too big.

Moderate and large floods will need to be dealt with by using a submersible pump, or sump pump. If the flood has come from an outside water source (heavy rain or snow fall) you will need to wait until the flood water has receded away from your house.

You will also want to be careful not to pump the water out too fast. If there has been a heavy rain or snow fall recently then there is likely a high amount of water pressure in the soil outside of your basement. The pool of water inside your basement may actually be balancing the outside pressure, and removing it too quickly could cause your basement walls to crack or crumble.

You will likely need to use an extension cord with your sump pump, so make sure the connection is away from the water. Wrap the cord around a railing, beam or other heavy object to make sure the connection with the extension cord stays dry.

Next, attach a garden hose to the pump and position the hose away from your house, preferably somewhere where the water can run into a storm drain or a sewer. If the water is fairly shallow you can use rubber boots and simply walk the pump to the lowest point in the basement. However, if the water is too deep to safely walk through, then tie a rope to the pump and lower it into the correct position.

Once you are ready to start pumping water, plug the extension cord into an outlet or generator. You can use more than one pump if you wish to speed up the process.

When pumping water out of your basement, start by removing one third of the water, or no more than two to three feet depending how serious the flood is. Once this is done mark the level of the water on the wall and leave it overnight.

If the water level has risen when you return the next day you will have to wait to remove the rest of the water. Mark the new water level and monitor it. Do not finish pumping out the basement until the flooding has stopped.

If the water level has remained the same then you can continue pumping it out. Repeat the same process as before, pumping out one third or two to three feet. Mark the level again and leave it overnight. Continue this until all the water has been removed from the basement. A wet/dry vacuum may be required to remove small pools of water that the sump pump can’t get.

During the water removal process, watch for any cracks or structural failure in the walls. If you notice any imperfections while you are pumping out the water stop immediately. The shifting of the foundation likely means the water outside the walls has not drained and is putting too much pressure on the walls.

Step 2: Cleaning and Sanitizing

Once the water has been removed from your basement the real work begins. You will want to clean up the area as soon as possible to prevent mold and mildew from growing. If the flood was caused by a sewage backup you will also want to sanitize the area and remove items that cannot be salvaged, as raw sewage contains a wide array of bacteria that pose a health risk to you and your family.

Safety First

A flood can introduce a number of health risks to your home, so you'll want to protect yourself accordingly. Wear protective clothing, including overalls, gloves and rubber boots. If there was any sewage water involved in the flood wear protective eye glasses and a facemask to protect yourself from harmful gases.

Avoid any electrical equipment or sockets until you are confident everything is completely dry. Even though the electricity has been turned off there is still a small chance of shock.

Remove Dirt

Once you have properly prepared for the cleanup you can start with any dirt and mud that was brought into the basement by the flood. Shovel out any debris while it is still wet. Any dirt sticking to walls and furnishings can be hosed off. Rinse everything several times to make sure you get it all. You will want to remove this dirt before it dries and hardens, as it will be much harder to get rid of once that happens. Use a wet/dry vacuum to remove any water left behind by the cleaning.

Remove Any Damaged Items

Some of your possessions will be able to be salvaged but other items will need to be thrown out, especially if raw sewage was involved in the flood. The following items should be thrown out:

  • All ceilings and walls that have been soaked or that have absorbed water. Remove wall materials at least 50 cm above the height.
  • Any flooring or carpet that has been deeply penetrated by floodwater or sewage.
  • Canned goods, herbs, vegetables and any other foods that came in contact with the flood.
  • All insulation materials
  • All less expensive articles that have been soaked, including particleboard furniture, mattresses and box springs.
  • Articles such as stuffed toys, furniture coverings, pillows, cushions and paper goods, as they cannot be properly sanitized.
Salvage Valuable and Savable Items

If cleaned properly many items can be salvaged. This includes:

  • Floors and carpet that have been minimally affected by the flood. Rinse and clean any flooring as quickly as possible. Clean and deodorize all carpets. If possible have them professionally cleaned.
  • Furniture that has been minimally affected by the flood. Scrub all furniture with antibacterial soap and water and place outside to dry (weather permitting) or steam clean.
  • Clothing. Scrape heavy dirt from washable clothes and machine wash them in hot water and soap, adding one cup of chlorine bleach to the wash water.
  • Items of particular value that show no visible contamination. Make sure to clean and dry all items thoroughly.
Sanitize and Disinfect

The final step is to thoroughly sanitize the entire basement all salvaged items. When using bleach and other cleaning supplies make sure there is ample ventilation to ensure the removal of any harmful fumes.

Wash all surfaces with chlorine bleach, using a solution of one cup of chlorine bleach per gallon of water. Surfaces that have not been directly affected by the flood can be cleaned with a solution of one part chlorine bleach to four parts cold or tepid water, mixed with a small amount of non-ammonia dishwashing detergent. Rinse all surfaces after cleaning.

Interior cavities should be cleaned with a solution of water, chlorine bleach and non-ammonia dish detergent. Any mold found needs to be killed with chlorine bleach. Wall cavities need to be completely dried before being closed.

Step 3: Drying Your Basement

To stop mold from growing you will want to make sure the walls, flooring and any items inside the basement are completely dried.

Open all the doors and windows to expose the basement to as much air as possible. Industrial blowers work best, but fans will do if you’re on a tight budget. If your basement heater was not affected by the flood, turn it to the highest setting. Although it may seem counter intuitive to run the heat while the windows and doors are open, it will help evaporate the water from your wet basement. If you leave the windows closed, the evaporated water won’t be able to escape, and they will stay inside your basement.

Once you are done with this process it’s a good idea to set up a dehumidifier it get rid of any remaining moisture. Keep the windows closed while using the dehumidifier and remember to empty the holding container regularly. Move the appliance around the room to get rid of as much moisture as possible.

Carpets need to be dried within two days. Depending on the size of the carpeted area you may need to hire a professional to dry it effectively.