Skip to Main Content

Water in Your Crawl Space

To protect your crawl space from water damage, read on to learn how to spot the problem signs, like dampness, rising humidity, mold growth, and other subtle indicators.

Schedule Free Inspection
water in crawl space

A crawl space is an important part of your home. It’s the foundation that keeps your house upright and stable. Knowing this, you can imagine how detrimental it can be to have water in your crawl space. 

Having standing water in your crawl space is never a good sign, as it indicates that there are some serious drainage problems going on in your foundation. Unfortunately, not a lot of homeowners are aware of the underlying issues in their crawl space. Because of this, many see problems arise throughout their home that could be prevented by waterproofing solutions for their crawl space. 

Learning how to detect the signs of crawl space water is the first step in getting the necessary measures in place. If you have the following problem signs, contact your local foundation repair experts: 

  • Mold Growth  

Mold growth in your crawl space is a clear sign that you have a moisture problem on your hands. Mold grows in dark, humid areas, which makes crawl spaces the perfect environment. They need water and organic matter to survive, and there’s plenty of that in your crawl space. 

When looking for a mold infestation, make sure to check the concrete walls and floor of the crawl space as well as the wood. On concrete, mold will look black or black-green. On wood, it can be white, black, green, red, or yellow depending on the kind of wood rot going on. 

Be very careful when inspecting your crawl space for mold. Immediate exposure might trigger allergies and irritate your skin, eyes, throat, and sinuses. The symptoms can be worse if you have a weak immune system or a pre-existing respiratory condition. Make sure to wear protective clothing when going into your crawl space and wash yourself thoroughly when you’re done, as you don’t want to spread mold spores once you’re inside. If you don’t want to expose yourself to the risks, call professionals for an inspection. 

  • High Energy Bills  

This is a problem sign that homeowners almost always miss when looking for crawl space problem signs. Your crawl space influences the energy efficiency in your home because of the stack effect. The stack effect is a term used to describe how air flows through your home. It enters your crawl space and influences the temperature inside. 

This makes it harder for your HVAC system to keep the temperature comfortable in your home. Because the systems work harder, it leads to an increase in your home’s energy bills. If your crawl space has a thermal control problem and unwanted air is managing to get through, moisture is able to get in as well. 

  • Strange Smells  

If you have been dealing with an inexplicable, foul smell in your home, you may want to check your crawl space. Because of the stack effect, 50 percent of the air that you breathe in your home comes from the crawl space. Not only does the hot and cold air infiltrate your home, but the strange, musty smell of the crawl space does as well. 

There’s no denying that, like basements, crawl spaces have a strange odor to them because of how humid they are. The smell of the moist air, mold, dust, and pests mix to create an unpleasant smell that travels upward toward your home. By waterproofing and insulating your crawl space, you’ll find that air in your home will smell better and feel cleaner. 

  • High Indoor Humidity  

If there’s water in your crawl space, all that humid air will rise into your home and raise the humidity levels. You can test out the humidity levels in your home using a hygrometer. The ideal range of humidity for your home should be between 40 and 60 percent. 

Controlling the humidity in your home can also help you save money during the summer. Humid air is a lot warmer than cold air, so your AC must work harder to keep things cool when the temperature rises. To control the humidity levels in your home and crawl space, a dehumidifier is an effective solution.

  • Wood Rot and Sagging Floors  

Wood rot is a frequent problem for crawl spaces with water. You can tell when wood is rotting visually by the discoloration caused by the fungal growth. Certain kinds of wood rot also grow soft lumps in flat, circular shapes. Others will leave square patterns on the wood that look like termite damage. Sometimes, there will be a white, cotton-like substance on the wood that looks as if somebody stuck white gum on the joist. 

All in all, if the wood isn’t smooth and evenly colored, it’s probably infected with wood rot. Compare the rotting wood to others in the crawl space. Wood rot can shrink down wood, so if the discolored one looks smaller than others, it’s wood rot. You can also touch the wood and feel for any soft spots since wood rot affects the firmness of the wood as well. 

Like any other mold growth, you need to be careful when checking your crawl space for wood rot. Exposure can be detrimental to your health, so leave it to the professionals if you have a compromised immune system. The consequence of wood rot is sagging floors since the wood joists are weakened by the fungus infestation. The wood isn’t strong enough to support the floor, so it becomes uneven and begins to sag. 

  • Wet Crawl Space Insulation  

Crawl spaces aren’t given much thought by anyone, even the construction crews that build them. Therefore, crawl spaces aren’t usually waterproof from the get-go and, if any waterproofing or insulation methods are put into place during construction, they are usually inappropriate for crawl spaces. 

This becomes apparent when you check to see what kind of insulation material you have for your crawl space. Usually, crawl spaces come with fiberglass insulation. Fiberglass is an absorbent insulation material made of fine strands of glass. The problem with fiberglass insulation is that because it’s absorbent, it takes in all the moisture in a crawl space. 

When absorbent insulation like fiberglass begins to soak up the humidity in the crawl space, the moisture begins to weigh it down until it falls apart. If your crawl space insulation is wet or deteriorating, it’s because of the moisture in your crawl space. 

  • Damaged Pipes  

Believe it or not, but water in your crawl space can damage your pipes to the point where they burst. When there’s humidity in your crawl space and the surface of your pipes are coated with moisture, the freeze-thaw effect does considerable damage during the winter. 

The freeze-thaw effect is a cycle in which moisture freezes, turns into ice, and then thaws. When water freezes, it expands by around nine percent. Expanding ice has the strength to push pipes past their tensile limit and displace their particles, it doesn’t happen immediately, but over the years, the freeze-thaw effect creates micro-tears along the pipes and causes them to burst open.  

  • Efflorescence 

Efflorescence is a white stain that appears on concrete. It occurs when moisture solutes the salt and minerals inside the concrete. As the moisture evaporates, it rises to the surface of the concrete, bringing with it the salts and minerals. The salts cluster up on the surface of the concrete, creating a white stain. 

Efflorescence is often confused for mold, but it’s just a mass of mineral deposits on the concrete. You can tell if the stain is mold or concrete when you touch the stain. If it feels rough and powdery, it’s most likely efflorescence. You should look at your fingers after touching it as well, and if it’s efflorescence, you should see a sheen of shimmering salts. 

What Causes Crawl Space Water? 

Crawl spaces are not often adequately built to handle water. This is a problem since water is such a damaging element to any foundation. Foundation experts can detect problem signs early and tell you what needs to be done to eliminate the water in your crawl space. Let’s examine all the possible ways water could have gotten into your crawl space. 

  • Soil Moisture  

If you have a crawl space with a dirt floor, the moisture could be seeping in from the ground due to the rising water table. The water table is an invisible line that indicates the start of the zone of saturation, which is where the soil is continuously saturated with groundwater. During the rainiest season of the year, the groundwater levels rise and the water table rises with it, inching even closer to the surface of the soil in your crawl space. 

In Alabama and Tennessee, the rainiest time of the year is in the spring, though it rains consistently throughout the entire year. Without proper waterproofing measures in place, your crawl space will flood with water often thanks to the rising water table.  

  • Crawl Space Vents 

Crawl spaces are typically ventilated with a small opening. The ventilation is meant to help with airflow, but not only does it hinder thermal insulation, it also allows water to get inside your crawl space. When it storms—a common occurrence in Alabama and Tennessee—the winds carry the rainwater into the crawl space from the open-air vent. If you have a negative yard grade and water flows toward your foundation when it rains, the open vent becomes an open door for the stream of water. 

  • Flooding  

Due to their proximity to the Gulf of Mexico, Alabama and Tennessee see a lot of hurricanes and tropical storms on a yearly basis, especially Alabama. The cities in these states most likely to experience flooding are Mobile and Nashville, respectively. 

A poorly waterproofed crawl space will have no defense against the flooding that occurs due to these storms. For homeowners in these states, it’s important to fully protect your crawl space from flooding by installing the proper waterproofing measures.

  • Leaking Pipes 

Plumbing issues can lead to crawl space water. Because your home’s pipe system is located in your crawl space, as soon as you notice an issue with your plumbing, you should also check on the condition of your crawl space.  

  • Cracks 

Your crawl space is partially underground, and the soil that surrounds it holds moisture. Cracks along the concrete can make it easier for moisture to soak through.  

  • Condensation 

Condensation is the opposite of evaporation. While evaporation refers to water turning into water vapor due to heat, condensation refers to water vapor turning into water due to cold air. For condensation to happen, the temperature in the crawl space needs to reach the dew point. The dew point is the temperature the air needs to be cooled to reach 100 percent moisture capacity. Essentially, it means the air in the crawl space is so saturated with moisture particles, it can no longer hold it. 

Water in Your Crawl Space


The only thing more alarming than finding water in your crawl space is finding out what it means for the health of your home and your family. Luckily, we’ve come far when it comes to waterproofing solutions, and we have many options for you to choose from to help keep your crawl space free of standing water, humidity, and mold. 

  • Drainage Systems and Encapsulation  

If there’s unwanted water anywhere in your home, an efficient drainage system is needed. AFS offers CrawlDrain™ for your crawl space drainage needs. It goes along the perimeter of your basement and it collects the water from the floor as well as the water from the walls. CrawlDrain™ is meant for crawl spaces with dirt floors, but if you have a concrete floor, we have BasementGutter®. Both these drainage systems can be connected to crawl space sump pumps. 

Encapsulation is also important for crawl space waterproofing. It involves installing thick sheets made of polyethylene so that the crawl space is completely sealed off. Our CrawlSeal™ vapor barrier is 20-mil thick and completely waterproof. There’s no better way to ensure that moisture doesn’t seep into your crawl space than with a protective vapor barrier like CrawlSeal™. 

  • Sump Pumps and Dehumidifiers  

Sump pumps are common in homes with basement, but did you know that you should have one in your crawl space? Homeowners in Alabama and Tennessee see a lot of rain and tropical storms throughout the year, so crawl space flooding is common. A sump pump guarantees that any water in the crawl space and in the surrounding soil gets collected and pumped out far away from the foundation. Our SafeDri™ series comes with a backup pump, so your crawl space stays safe if the main pump shuts down. 

A dehumidifier is also essential to keep the humidity levels in the crawl space low and prevent mold growth. Our industrial-grade dehumidifiers are nothing like the ones you have in your home. These are powerful machines capable of keeping the most humid part of your home dry despite all the surrounding moisture. 

  • Negligence  

It was believed long ago that having a dirt crawl space with ventilation was the way to go about building a foundation. Now, we understand that crawl spaces should be enclosed and have proper drainage systems in place to avoid the consequences of foundation humidity. However, even if construction crews know this, they still stick to the traditional way of doing things. 

This is because it is cheaper to build a crawl space as is than to build it with waterproofing solutions. As long as they build the crawl space up to code and nothing falls apart after they’re done, it shouldn’t matter if the crawl space will cause problems in the future. This way of thinking is what pushes construction companies toward building crawl spaces that lack what they need to stay dry. 

  • Outdated Building Codes 

Depending on where you live, building codes might not have waterproofing solutions for crawl spaces written in. A lot of these codes actively encourage ventilated crawl spaces, so many contractors that follow these codes will not go against the rules. 

Even if a contractor wanted to waterproof a crawl space, it could be a bit difficult to do so because of the outdated building codes. Since the codes don’t say anything about waterproofing, it would require running a lot of time-consuming, frustrating errands to get the permits approved, so many simply don’t bother with it. 

Crawl space water is difficult to prevent if you have a ventilated crawl space. When your crawl space isn’t properly protected, that is when problems with moisture arise.  

  • How to Prevent Crawl Space Water  

The only true way to protect your crawl space from moisture problems is by hiring your local experts and installing waterproofing solutions. Without these solutions, your crawl space is vulnerable to many things. Rain, flooding, and soil moisture are all naturally occurring events that you can’t prevent. 

By waterproofing your crawl space, you’re ensuring that standing water in your foundation never becomes an issue again. Without a sump pump, dehumidifier, vapor barrier, and drainage pipe, a simple leak can cost you thousands in repairs. 

  • How To Help Your Crawl Space  

Once you have all your crawl space waterproofing solutions in place, there is a key element that helps the machinery in your crawl space remain efficient for years to come. This is especially important in rainy places like Alabama, where sump pumps often malfunction after storms. 

To avoid overworking your sump pump and dehumidifier, you need to check your yard’s grade every few years to make sure it’s positive. A yard with a positive grade will have water flowing away from the foundation when it rains. The terrain changes with time, so even if you bought the home with a positive yard grade, you might be due for a re-grading job. 

Call AFS Foundation & Waterproofing Specialists for Crawl Space Waterproofing and Repairs 

Water in your crawl space should be considered a red flag for any homeowner. If you don’t know where to go after discovering such a problem, AFS has the solution. We’ve been helping the homeowners of Alabama and Tennessee keep their crawl spaces free of water since 2000. We are trusted local experts who take pride in our efficient, customer-friendly approach to home repairs. We service Birmingham, Huntsville, and Mobile, Alabama as well as Nashville, Chattanooga, and Knoxville, Tennessee

Getting in contact with us is simple: Give us a call or use our online contact form. We’ll send one of our field experts to your home for a free inspection. A detailed rundown of the repairs and a cost estimate will be given to you the very same day. Because of our innovative solutions, our installations are quick and non-invasive. Your crawl space water problem will be gone before you know it. 


Schedule Free Inspection
Schedule Free Inspection

Publish Date:

Last Modified Date:


Birmingham, AL

130 Interstate Commerce Crt. Bldg. 100 & 200
Alabaster, AL 35007

Chattanooga, TN

214 Industrial Park Dr.
Soddy-Daisy, TN 37379

Columbus, GA

2701 Opelika Road
Phenix City, AL 36870

Huntsville, AL

2415 Jordan Road
Huntsville, AL 35811

Knoxville, TN

3028 E Governor John Sevier Highway
Knoxville, TN 37914

Mobile, AL / Biloxi, MS

3131 Hamilton Blvd.
Theodore, AL 36582

Montgomery, AL

445 Dexter Avenue, Suite 4050
Montgomery, AL 36104

Nashville, TN

1519 Heil Quaker Blvd.
LaVergne, TN 37086

Pensacola, FL

89 W. Hood Dr.
Pensacola, FL 32534