Water In Crawl Space After Heavy Rain: Is It Normal?

Water In Crawl Space After Heavy Rain: Is It Normal?

Water In Crawl Space After Heavy Rain

Is It Normal To Have Water In Crawl Space After Rain?

It is not uncommon to have some water in the crawl space after heavy rain. Any water that does make it into the crawl space after a heavy rain should drain away or evaporate in a short time. Nevertheless, water intrusion that goes undetected for a long time can cause serious damage if not remediated.

surface water in crawl space after heavy rain (normal)

We have already discussed the general issue of water in the crawlspace and particular situations in the foundation that this generates like the deterioration of the air quality and the problems when trying to sell the house with this issue.

Sometimes there are serious issues when we detect standing water in the crawl space despite the lack of rain, without leaking water heaters, without flooding due to a sudden rise of the water table, or visible hydrostatic pressure because this pressure occurs in the basement and not in a crawlspace.

Here we deal with the question, is water in crawl space after heavy rain normal, so it is not a sudden rise in the water table level or flooding but usually happens when it rains.

I will also explain which are the solutions that I suggest implementing after we have removed and dried out completely the wet and humid surfaces.

Those solutions will prevent the future occurrence of the accumulation of water, namely through the execution of a crawlspace waterproofing, usually by installing a vapor barrier and probably a dehumidifier.

Is water in crawl space after heavy rain normal?

Water level (1)

Puddles of water in the crawl space aren’t good, but the water itself won’t ruin your home. It’s the water vapor (or moisture) that causes rot, mold, energy loss, and attracts pests. And these problems don’t just stay in your crawl space. As much as 50% of the air upstairs comes from below – this means mold spores, musty smells, and humid air that dust mites love.

A flooded crawl space after heavy rain may be all too common in many homes, but it is not “normal.” Theoretically, the crawl space under your house is designed to stay dry in all weather. When it doesn’t, water damage ensues. Wood rot deteriorates structural components, toxic mold growth gains a foothold and infects the entire house and insects and vermin thrive in the wet, dark environment. You can’t do anything about episodes of prolonged or heavy rain that typically precede a flooded crawl space. What you can do is take a number of steps to keep water out and keep the crawl space dry, the way it was designed to be.

Divert water away from the foundation. Rainwater pooling around the foundation seeps into the crawl space through cracks and other openings. The landscape around the perimeter of the house should be graded so water naturally flows away instead of forming puddles that soak into the soil.

So the solution can be to install a sump pump along with a perimeter trench known as French drain. Also, install metal vent wells in front of each foundation vent. Furthermore, regrading the soil lower and away from the vents. In extreme cases, water pools around, rises up and chanells through the foundation vents.

The water that can enter your crawl space after heavy rain is not only the one from your roof. We have to add the one coming from the garden landscape if you have red clay soil, from a hill or slope outside the house, from the water table in that area, from outside seeping from the foundation vents, and the accumulation of hydrostatic pressure.

Water in a crawl space after heavy rainfall is also a common problem if ignored. Sometimes the ground becomes so saturated, it can’t hold water anymore. Water will pool around your home if this is the case, and water could flood into the surrounding areas—your basement, and your crawl space.

Additionally, surface water flooding is a result of heavy rainfall, but could be a problem if downspouts are not turned away from the house. Water from heavy rainfall should be directed away from the foundation of your home.

It should not be surprising to see some water in the crawl space after a heavy downpour. When a large volume of rain falls within a short period of time, it can temporarily overwhelm the systems designed to funnel most of the runoff and surface water away from the home. The accompanying winds can also work to drive water through openings that normally protect your home (such as crawl space vents and under-roof shingles or flashing).

it’s always wise to shine a flashlight under the house after a heavy downpour to make sure there’s not a lot of water accumulating.  

Landscape beds and nonporous surfaces should slope away from the foundation so that water is not trapped against the structure’s walls. Downspouts and corrugated drain pipes should be used to help move water draining from the roof at least 10 feet away from the home whenever possible. Even then, some water may eventually find its way into the crawl space.

It’s not uncommon to have some water under the home after a heavy rain. Ideally, the home should have been constructed with a positive drain toward the lowest corner of the crawl space. Any water that does make it into the crawl space should drain away or evaporate in a short time.

When this water becomes standing water, however, that’s when water in a crawl space is a problem. 

Finding standing water in your crawl space can lead to a lot of issues. The crawl space sits right in the area of your foundation. Water will damage concrete foundation and wooden supports, and decrease your foundation’s durability and life expectancy. Water will eventually decrease the structural integrity of your home, making it dangerous to inhabit.

It is important to regularly inspect your crawl space. Water intrusion that goes undetected for a long time can cause serious damage if not remediated. It is best to view your crawl space at various times in order to have a basis for comparison after heavy precipitation. A little water in your crawl space after a downpour may not pose a serious problem; but prolonged standing water must be dealt with.

Finally, if you are unable to access the crawl space yourself, this might be a good time to have your home checked by a qualified professional. Most of us only think of hiring a home inspector when we are buying or selling a home, but they can inspect all or part of your home at any time. The few dollars invested in an inspection today could save you hundreds of dollars over the long run.


If you have a crawl space that leaks when it rains – even if it’s only sometimes – getting the water problem under control should be the first step you take in fixing your overall crawl space problem.

Groundwater leaks and pooling water add humidity to your crawl space. A home with a dry crawl space is less attractive to mold, dust mites, termites, and other pests.

Getting rid of crawl space humidity can save you 15-25% on your heating and cooling costs. The exact savings will depend on several factors, including:

First Urgent Things To Do After Finding Water In Crawl Space After Heavy Rain

There’s so much to take care of after any type of storm damage especially when you have to deal with a flooded crawl space. Knowing what to do first makes a big difference in personal safety and property recovery.

  • Call your insurance company, and get the claims process started right away.
  • Turn off the electricity to the lower levels of your home before entering the crawl space.
  • Document crawl space water damage with pictures for the insurance adjuster.
  • If you have any stored valuables that can be saved, contact a restoration company.


After you have completed your flooded crawl space cleanup routine, the next step is to determine what is causing the water issue in the first place. Some of the more common causes of flooded crawl spaces include:

  • Drainage Issues: If your crawl space becomes flooded when it rains heavily, you could likely be facing drainage issues caused by inadequate guttering or downspouts, improper grading of your property, or defective window wells.
  • Soil composition: My own experience is that the rainwater saturates red clay soil quickly, goes past the foundation and penetrates the crawl space. So the rainwater is actually coming from the garden or yard that can be within your property or outside it. In the case of red clay, the soil has to be regraded away from the foundation and metal vents should be installed.
  • Sump Pump: A missing, defective, improperly installed, or inadequate sump pump can allow rising groundwater to seep into your crawl space.
  • Cracked Foundations: Even when the proper systems are in place to prevent crawl space flooding, a cracked foundation will still allow water and excess moisture to enter.
  • Broken or Leaking Pipes: Leaking water lines can cause a flooded crawl space as well. If your home has older pipes, this increases the risk for crawl space flooding significantly.
  • Sewage Backup: Clogged sewage lines or an overwhelmed sewage system could not only cause a flooded crawl space but could pose hazards to your health also.
  • Walls: Think of concrete like a sponge. Many concrete structures, both new and old, are porous, especially basement and crawl space walls and foundation supports. Concrete can also become “soft” as it ages, allowing water to seep into crawl spaces. The water passing through concrete will cause expansion and contraction of the block walls, and eventually lead to cracks. I see cracks frequently where the bocks meet the footing.
  • Torn vapor barrier: Remove the torn vapor barrier. Wait until the water in crawl space after heavy rain dries and replace the shedded vapor barrier for a new one.
  • Condensation: Not very frequent, but you can see condensation in the walls and in the ABS (Acrylonitrile butadiene styrene) drain lines.

Consequences Of Stagnant Surface Water In Crawl Space After Heavy Rain

The biggest problem would be mold. It can grow on hard surfaces like ducts and joists, not to mention your home’s insulation. Once mold begins to grow it can spread through your home’s ventilation system and cause health problems for you and your family.

Residual water becomes stagnant and putrid, thus providing a breeding ground for bacteria and germs. Water insects, mosquitoes, beetles, as well as small rodents, are drawn to the dark, damp environment of a crawlspace and will establish a base beneath your home’s foundation. Standing water may also cause wood to rot, which can lead to the degradation of structural components in your house.

  1. Higher Energy Bills: A home with a dirt crawl space costs more to heat and cool. The reason for this is damp air takes more energy to heat or cool and more energy used means higher energy bills.
  2. Mold: Mold loves moisture. And mold loves to eat dead organic materials, like wood, paper, and cardboard. The bad news is most crawl spaces have lots of moisture, as well as wood and other organic materials for mold to grow on. Mold also likes to eat dead insects and there are usually lots of those in the crawl space too. Vents in the crawl space provide an open invitation for insects and pests. Vents also let in moisture, creating the ideal home for mold.What’s worse is mold releases airborne spores that eventually make their way upstairs. Mold in your crawl space isn’t good for your health or your property value. Nobody wants to buy a house with mold.
  3. Mildew: Normally mold and mildew go together. The difference between the two are in their intensities, but they are both equally as unsafe if gone unnoticed. Mildew is a surface fungi, while mold is the sign of a larger infestation of fungi. This will not only damage the wood in your crawl space, but also have adverse effects on a person’s health.
  4. Dust Mites & Pests: Dust mites thrive in humid environments, so they love homes with a dirt crawl space underneath. Dust mites are microscopic parasites that live in your bedding, carpet, and furniture. Dust mite droppings float in the air and can trigger allergies and asthma. Other pests, like termites, spiders, mice, rats, and snakes love damp, dirt crawl spaces too. Nothing attracts pests more than small, dark spaces, but water is their best friend. Standing water will attract pests and small animals and sometimes, even microscopic plant life. Termites are likely to welcome themselves into your home through a damp crawl space, swiftly aiding in the structural damage of your home.
  5. Animals that burrow under concrete. AsI described in this article, water reaches animals that burrow under concrete and other animals that dig in the foundation. They do not need to adventure outside the foundation for water. They affect the crawl space air quality too.
  6. Moisture that can rot the floor joists. The moisture can rot the floor joists and force you to sister them to reinforce the framing, a process with some complexities, specially for 2×4 and 2×6 joists. Cover your joists with Fiberglass R21 batts.

Discharging The Water Outside The Crawlspace

If you find yourself with standing water in your crawl space after heavy rain or plumbing problems, the first thing you will need to do is remove the water as soon as possible. If you simply wait for the water to go away on its own, you could end up with extensive damage to your home. Sucking the water up with a “wet-dry vac” or pumping it out with a commercial pump machine (depending on the amount of water present) are typically the most effective methods.

How to Dry Out a Wet Crawl Space

Once you have removed the water from your crawl space, it is essential that you dry out the area thoroughly. Never simply allow the space to air dry. Since wood will soak up moisture at an alarming rate, and cool concrete surfaces retain water much longer than most other materials, a significant amount of moisture will likely remain even after you have removed the puddles of water.

A dehumidifier is extremely effective at removing excess moisture from a damp crawl space. A high-quality machine will eliminate moisture in the air, drastically reducing the chances of mold or mildew development.

Vacuum To Remove Water

Invest in a wet-dry vacuum. If your wet crawl space is a minor issue, meaning there’s not much water present, use a wet-dry vacuum to remove the water. A hose draws the water into the vacuum compartment to be discarded outside.

Don’t allow your crawl space to air dry after this step. Concrete is much cooler than other materials, so it holds moisture longer, and wood absorbs water almost as easily as sponge. Even if you have the pools of water cleared out, moisture will be left behind.

Use a dehumidifier to quickly dry out the space. This will remove moisture from the air and prevent mold growth. 

Simply cleaning out crawl space water, however, will not prevent any issues from resurfacing in the future. There are some other problem areas to check and possibly fix in order to prevent water in a crawl space.

Crawl Space Flooding Solutions

Once you have determined the cause of your crawl space flooding problems, it’s time to evaluate adequate solutions. While there are some things that you can fix yourself in order to prevent a flooded crawl space in the future, you may need the assistance of an experienced professional for other remedies.

Okay, enough about all the problems that can occur when water floods your crawl space. How about a solution? There are plenty of options you can take to help you eliminate crawl space flooding.

You can have a sump pump professionally installed. Remove water and protect your crawl space or basement from flooding with a reliable sump pump. A sump pump will help keep your crawl space dry by automatically pumping and channeling water away from the foundation of your house.

Another good option is a French drain. A French drain is just a gravel lined trench around the perimeter of the foundation that connects to a pipe and carries water away from the home.

Always try to divert water away from the foundation because rainwater pooling around the foundation seeps into the crawl space through cracks and other openings. The landscape around the perimeter of the house should be graded so water naturally flows away instead of forming puddles that soak into the soil.

Keep rain gutters clear and unobstructed to prevent cascading overflow that also permeates soil around the foundation. Make sure gutter downspouts are long enough to discharge water sufficiently far from the perimeter of the house and prevent pooling. You can always add gutter extenders so water flows even farther from the home’s foundation.

Suit up for crawl space water removal with work boots and heavy gloves. You may also need to rent a pump, a wet-dry vac, heavy fans and a large dehumidifier.


Don’t try to salvage belongings that have been under water for more than a few hours. Dispose of all wet materials including soaked insulation and submerged vapor barriers.

Correcting Drainage Issues

Consider a foundation drain system. Embedded in a narrow, gravel-filled trench around the perimeter of the foundation, a perforated pipe catches water as it seeps into the soil and conveys it away from the house, out into the yard or all the way to the street.

We have suggested already to setup drainage solutions as a way to address hydrostatic pressure in this article. The principle is the same: divert and drive water away from the foundation instead of just waterproofing.

Divert water away from the foundation. Rainwater pooling around the foundation seeps into the crawl space through cracks and other openings. The landscape around the perimeter of the house should be graded so water naturally flows away instead of forming puddles that soak into the soil.

If you have determined that improper sloping or grading is the culprit of your flooding crawl space woes, a repair can sometimes be extensive. It might be wise to consult with a professional.

Check The Vapor Barrier

Take all the shredded and torn vapor barrier. Seal any visible cracks in the wall, for example, I found at home some cracks where the blocks meet the footing.

Keep Rain Gutters Clear

Keep rain gutters clear and unobstructed to prevent cascading overflow that also permeates soil around the foundation. Make sure gutter downspouts are long enough to discharge water sufficiently far from the perimeter of the house and prevent pooling.

Downspouts and gutters are specifically designed to direct excess rainwater away from your home. Check to see if your drainage system is clogged, damaged, or not directing water flow in the correct direction. Additionally, it’s a good idea to install extensions at the base of your downspouts to discharge water at least four feet away from your home.

Sump Pump

This is a submersible pump in a hole with a float arm that will drain the water if water raises the float to a certain height. 

Especially if you experience frequent flooding of your crawl space, it is recommended that you have an adequate sump pump installed. If you already have a sump pump in your crawl space, inspect it to ensure that it is working properly and has been installed correctly. An experienced professional is recommended to properly install, inspect and repair crawl space sump pumps.

Heavy rains also cause ground water to rise up into the crawl space instead of leaking in. Installed in a basin embedded in the ground inside the space, a sump pump activates automatically as ground water enters the basin. The pump conveys water through a discharge line that usually terminates out in the backyard.

Because severe weather that floods a crawl space may also cause power outages, it’s a good idea to install a sump pump with battery backup feature.

If you have a sump pump in the crawl space, make sure it’s working. Even if it is operating properly, back it up with another pump to move out standing water as quickly as possible.

Adding a sump pump is the first line of defense in keeping water out of the crawl space. It’s necessary to install a sump system with a sturdy sump liner, an airtight lid, and a reliable pump. The SmartSump System offers all of these features and it’s designed specifically for crawl spaces.

Just as I suggested before, it is preferable a good sump pump system with a battery backup pump.


Use a wet vac to remove water left behind after pumping. A push broom comes in handy for moving water in hard-to-reach areas to levels you can finish off with the wet vac.


Position large fans and at least one dehumidifier on level surfaces throughout the crawl space. Let the equipment run for at least three days, and regularly empty dehumidifier reservoirs.

Important Power Tip: Operate pumps, wet vacs, fans and dehumidifiers with heavy-duty extension cords connected to GFCI outlets located safely above the crawl space.

Order A Foundation Inspection

Since even small cracks in a foundation can result in water entry and lead to much bigger problems in the future, it’s a good idea to inspect your foundation frequently. If you notice cracks, have them repaired by a professional immediately to avoid a flooded crawl space or other severe property damage.

Inspect The Piping Network

Water lines carry water to various areas throughout your home. Old, worn-out pipes, those that have been exposed to extreme temperatures, and those that were improperly sealed can sometimes fail. When broken or leaking pipes are causing your flooded crawl space, the damage to your home can be extensive, and your utility bill could go through the roof. Have a professional inspect your water lines and repair or replace those that are at risk of failing or are already leaking.

Trenchless Pipe Solutions

Sewage Backup

Sometimes heavy rains can overwhelm a sewage system. When too much water is trying to get through a sewage system all at once, sewage can sometimes back up through drains. Additionally, clogged sewage pipes can come up through your drains as well. Sewage backup can result in crawl space contamination, extensive water damage, and health problems. If you suspect that your sewage system could be the culprit for a flooded crawl space, it is important to contact a professional for an immediate solution.


Inspect piers, ducts, joists, overhead subflooring and the interior foundation for mold. If you see any signs of fungal growth, clean it up, and treat affected areas with mold remediation products.

Plant some trees

A minor solution, is planting trees in a wet area of the garden landscape that will absorb part of the water. This is just a secondary solution to apply.

Inconvenience Of DIY Approaches To Analyze Water In Crawl Space After Heavy Rain

If your only entrance under the house is through an exterior opening, consider how you’ll manage to get equipment in and out. Even a small entry door through a closet or pantry room can be a problem especially with no more than 4 to 5 feet of clearance overhead.

Water in crawl spaces after a heavy rain is usually contaminated with insect and animal debris mixed with mold and damaged materials. Crawl space insulation and ductwork in older homes often contain asbestos.

Insurance For The Case Of Water Damage Due To Heavy Rain

If you spent major money on remodeling your kitchen and a water leak destroy the cabinets and the hardwood or the tile that you have worked hard to install, your insurance claim would assist in correcting your kitchen water damage. The only problem is most insurance companies aren’t going to help you to fix your crawl space. Many insurance companies consider crawl space flooding to be a maintenance problem which is not covered.

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BY M. Kogan

Hello, I am Marcio. I am an architect and designer, alma mater is Mackenzie. Retired in theory, but an architect never retires completely. Along with architectural projects, I am a filmmaker and have completed some short documentaries. Filmmaking and design are my passions. In HomeQN I write about home decoration and foundations. The goal is to teach homeowners to DYI as much as possible, and when this is not possible, enable them through knowledge, to evaluate service quotations and choose the best service technicians.

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