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Why Does My Crawl Space Flood When It Rains? (And How to Prevent It)

Why Does My Crawl Space Flood When It Rains? (And How to Prevent It)

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What an awful experience when rain turns your crawl space into a messy, flooded area.

If you’ve been through it, you must be wondering: why does my crawl space flood when it rains?

Well, if your house foundations are cracked, this can result in a flooded crawl space after rain. An erroneous sewage system can also stand behind this issue.

In addition, problems with installing your gutter system and downspouts can be possible causes.

In this post, we’ll break down why crawl spaces may flood after rain. We’ll also provide the best solutions to address this issue.

The Four Reasons Why Your Crawl Space Might Flood When It Rains

If your crawl space becomes submerged with water after heavy rain, here are a few common reasons for this issue:

1 – Cracks in the House Foundations

House foundations might develop tiny cracks over time due to multiple factors, including harsh climate conditions.

These fissures are normal and don’t significantly affect the house’s strength.

Though, they may allow accumulated underground water from rains to penetrate and enter your crawl space.

The larger these cracks become, the more water can enter your crawl space during and after heavy rain.

2 – Sewage System Issues

The massive amount of water that goes into your sewage system during heavy rains can overwhelm it. As a result, the system pipes can flow in the opposite direction.

This can lead to water getting into your crawl space and other places the pipes pass through.

3 – Incorrectly Installed Gutter System

The gutter system’s primary purpose is to protect your house foundation from possible damage rainwater can cause. It does this by diverting the water away from the house.

Nonetheless, if the system is incorrectly installed, it can have the opposite effect. It might direct rainwater toward the house foundation exposing it to more risks.

As a result, rainwater may penetrate the foundation and enter the crawl space.

Similarly, if your gutter system is clogged with leaves or debris, this can cause it to flow improperly.

As a result, the water might spill over the house’s sides and seep underground, entering your crawl space.

4 – Wrong Downspouts Positioning

If your house downspouts are positioned improperly, they can cause rainwater to flow toward the house instead of away from it.

In this case, rainwater can eventually end up in your crawl space.

Moreover, some people even make the mistake of not installing downspouts to their gutter system. This can also result in pools of water accumulating next to their houses after rain.

Why Should You Fix Your Flooded Crawl Space as Soon as Possible?

When water enters your crawl space, it can cause a significant mess. However, this isn’t the only problem that stagnant water may cause.

Here are four issues that can result from water accumulation in your crawl space:

  • Forms mold and attracts airborne spores: There’s a high probability of mold developing wherever there’s excessive moisture.
  • Increases costs of bills: Humid air is harder to cool or heat than dry air. So, it’ll require more energy to condition it. This means it will result in higher electricity bills.
  • Attracts dust mites: These parasites can first develop in the crawl space and then quickly spread into your house. They can invade your furniture, bedding, and carpets.
  • Creates an ideal environment for pests and harmful animals: Your crawl space can become a destination for spiders, termites, rats, mice, and even snakes.

How to Fix Crawl Space Flooding? 5 Simple Steps

To remove the stagnant water in your crawl space and dry it off, you need to follow these steps:

1 – Pump the Water Out

Use a general-purpose pump to pull the water from the space and push it away from your home.

To do so, position the suction hose in the water. Then, place the drainage hose at least 10 feet away from home.

After that, turn on the pump and monitor it. Change the suction hose location when needed. Keep running the pump until you remove all the standing water.

2 – Remove Any Wet Materials

You need to remove any wet materials from the crawl space. This includes debris, stored items, and insulation.

That’s because keeping these items in the crawl space will prolong the time needed to dry the place. They will also increase humidity in the area.

3 – Remove the Residual Water & Clean the Space

When you finish pumping out the water, there will still be a small amount remaining. Use a wet vac to remove this residual water.

Additionally, remove any formed mold or moldy objects in the crawl space. Then, start to clean the surfaces to stop the spread of mold.

4 – Check for Wiring Damage

Look for any wiring damage in the space. If you find any, you need to repair it urgently. That’s because such an issue can make the whole area unsafe.

5 – Dry Off the Space

After cleaning the place, you need to reduce the high humidity caused by the flooded water. To do so, you’ll need to use a dehumidifier.

If your crawl space is small, use a large room dehumidifier. Still, if the area is spacious, you’ll probably need to rent a commercial-grade unit.

Run the dehumidifier for ten hours at 30 to 45 percent. After that, check the area to determine if it requires further humidity reduction.

In addition, place two or three electric fans to blow air toward the surfaces to speed up the drying process.

How Do I Protect My Crawl Space From Flooding After Rains?

You can protect your crawl space from rainwater flooding in a few ways. Here are they

1 – Set Up a Sump Pump

Installing a sump pump is one of the most effective ways to prevent water from flooding your crawl space.

A sump pump is a device that is installed beside the home foundation to divert groundwater away from it.

When rainwater accumulates underground and attempts to enter your crawl space, the sump pump holes collect it. At this point, the device automatically activates.

Then, the pump starts to work by pulling water and pushing it through the drain pipe. This drain pipe is extended to a location far from home.

The pump continues running until it disposes of all the accumulated water.

2 – Fix Your Gutter System

Check your gutter system for any issue that can contribute to water seeping into your crawl space.

If your gutter system has leaves or debris stuck in it, you’ll need to remove them to unclog it. This will adjust the water flow, reducing the probability of it entering your crawl space.

As a part of this inspection, you need to look at the downspouts. Check if they direct rainwater far enough from the house foundation.

If not, you need to modify them yourself or seek help from a plumber.

3 – Install Downspout Extensions

If, for any reason, your gutter system doesn’t have downspouts, you need to consider adding them.

By installing downspout extensions, you can drive water at least 6 feet away from your home’s foundation.

This will decrease the chances of water accumulating around the house foundation and entering the crawl space.

4 – Fix the Cracked House Foundation

One of the possible solutions to prevent water from entering the crawl space is to fix any cracks in the house foundation.

However, you should first assess the cracks. This is to determine if they significantly impact water penetration or if it’s okay to leave them as are.

To do so, you need to consult a structural engineer or foundation contractor for assistance.

5 – Repair the Sewage System

Check if your sewage system functions properly during periods of heavy rain. If you notice any leaks or water flowing in the wrong direction, you need to repair the system.

In most cases, you’ll need the help of a professional plumber to do this.

Who to Call for Water in the Crawl Space After Rain

If the rainwater floods your crawl space, here are three professionals you can contact for assistance:


A plumber can assess the situation and identify where the water comes from.

They can also check your gutter and sewage systems for issues contributing to water seeping into the area.

Water Remediation Specialist

In severe cases, like when the water floods your area, you should call a water remediation specialist.

These specialists have the equipment needed to remove stagnant water from crawl spaces.

Moreover, they can provide practical solutions to prevent similar occurrences in the future.

Structural Engineer

If rainwater has caused severe damage to the home foundation, you need to contact a structural engineer in addition to a water remediation specialist.

A structural engineer can provide solutions to any foundation problem resulting from rainwater. This is to protect the house foundation from further potential damage.

Final Thoughts

Why does my crawl space flood when it rains? Your crawl space can become flooded due to a few causes.

Cracks in your house foundation or issues with the sewage system can be the root of the problem.

Likewise, if the gutter system is incorrectly installed or directed, this can also lead to the same issue.

Given that, you can refer to the steps above to prevent future flooding in your crawl space.

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