Water In Basement After Rain: Causes and How to Fix

Discovering water in the basement after rain can be more than a little overwhelming. You might even be tempted to pick up the phone and call in the pros for help. Resist the urge. More often than not, the fix to a leaky basement is one you can handle yourself.

Clearing a clogged gutter or extending a downspout may be all that’s needed to prevent rain runoff from finding its way to the foundation and basement. Other fixes may involve covering a window well or sealing cracks and holes in the foundation walls and floor.

In this article, we’ll review how to identify if the water in your basement is indeed the result of rain. We’ll also help you determine what’s causing the problem, suggest simple solutions, and help you decide when it’s time to hire a professional.

Water In Basement After Rain

How to Tell Where Water Is Coming Into Basement?

There can be other reasons water is collecting on the basement floor, which can sometimes make it difficult to determine if rain is the culprit.

A slow main drain that backs up through the basement drain when handling a large volume of water could be the problem. You might also have a leaky washing machine or water heater.

The most obvious way to determine if the water is due to rain is if the basement only gets wet after a hard rain. Are there puddles on the basement floor after heavy rain? Is water trickling down the walls from a crack, hole, or basement window? Both are telltale signs that the water collecting in your basement is from rain.

Common Causes of Water Leakage in Basement After Rain

Cracks, cove joints, and basement windows are each common causes of leaks in the basement. Below, we’ll review how to identify each type.

1. Cracks and holes

If rainwater is seeping into your basement, more often than not, it’s coming through cracks in the foundation walls or floor. This is relatively easy to spot unless your basement is finished, in which case you’ll need to remove drywall or flooring to locate the problem.

Look for stains on the drywall or floor to help determine where the crack is. Once you’ve found the crack or hole, you can repair it using a hydrostatic concrete patch.

Basement foundation leaking

2. The Cove Joint

The joint between the wall and floor of the foundation is also a common place where water can get into the basement. After heavy rain, the groundwater levels in the soil rise, creating pressure to push moisture into any cracks or gaps in the foundation.

The cove joint is a gap between the wall and the floor that allows the floor and walls to expand and contract without buckling against each other as the house settles.

It’s also a common place where water can seep out of the walls. Unlike cracks, you cannot seal a cove joint with cement or sealant. The sealant will either redirect pressure from the groundwater to other weak points in the foundation or fail.

To repair a leaky cove joint, you’ll need to install a drainage system in the basement.

3. Basement Windows and Doors

While window wells are typically protected from rain, they do lie below ground level, so that makes them a potential place for water to collect. Poor grading or landscaping that traps water can cause water to collect in the window well, putting pressure against the window itself.

Even window wells that have a protective overhang can collect water during windy storms. Once that happens, any crack or gap in the window will allow water to leak into the basement.

If water is collecting in a window well, check to see if the window well has a drain. If so, it may have a clog that needs to be cleared. If the drain is fine or if the well doesn’t have a drain, you may need to find a way to redirect rainwater away from the window well.

A walkout basement door can also be the source of a leak. Any water that collects outside the door will cause water to seep through the seals around the door and into the basement.

If there is water running under the door, check the downspouts and gutters to see if they are dumping water just outside the door. You also may need to check the grading around the entrance to make sure water is not being directed towards the basement door.

4. Clogged Gutters and Downspouts

Water seepage in basement after rain

If water is allowed to pool around the exterior of your foundation walls, there’s a much better chance of it infiltrating the basement. Check the downspouts to see where the water is coming out. The downspouts should send water to an area that directs it away from the foundation.

If it isn’t, use a downspout extender to direct the water further away from home. Also, check the gutters. Clogged gutters can cause water to overflow the gutters, sending water cascading to the ground, forming puddles around the foundation.

5. Hydrostatic and Lateral Pressure

Hydrostatic and lateral pressure occurs when water saturates the ground around and under the foundation, creating pressure against the foundation. This pressure causes water to seep through cracks in the walls or floor.

Poor grading or problems with the gutters and downspouts can cause water to collect around the foundation, then soak into the ground.

Hydrostatic pressure not only causes water to enter a home, but it can also lead to bigger problems. The saturated soil can cause uneven settling or create enough pressure to cause cracks in the basement floor.

Fix this issue by making sure all downspouts direct water far away from the foundation. Also, make sure the ground around the foundation is properly graded so that water runs away from home.

6. Backflowing Through the Drain

Basement Floor Drain Backing Up

Though the water in your basement may indeed be rainwater, it may not have anything to do with the foundation, window wells, grading, gutters, or downspouts in your home. Many cities have aging sewer systems that become overwhelmed during heavy rain.

When this happens, the sewer system can back up, pushing water back into homes, causing sewer water to come up through the basement drain.

A backed-up drain can look a lot like your basement leaks. If water is pooling around the basement drain during heavy rain, there’s a good chance this is what’s happening.

Water backing up through floor drain due to heavy rain is a warning sign you must take seriously.

City sewer backups can, in some cases, cause catastrophic damage and municipalities are rarely liable for the damage. Install a backflow valve that prevents water from flowing back through the basement drain.

7. Landscaping

Sometimes well-intentioned landscaping can direct water into the basement. People often plant flower beds and shrubs around the foundation, mulch the area, then use timbers, pavers, or landscaping edging to enclose the bed.

Some homeowners will even add edging as a means of preventing rainwater from a downspout from washing mulch from the garden beds into the yard. This seemingly innocuous solution can have grave consequences on your foundation.

The edging, pavers, or timbers act as a barrier that prevents water from flowing away from home, allowing it to pool against the foundation. This can cause water to collect in window wells, seep through cracks, or eventually build up and create hydrostatic pressure around the foundation.

What Problems Can Rainwater in the Basement Cause?

Leaky basement

Depending on how much water seeps into the basement when it rains, failing to address water in the basement can have significant consequences if left unchecked.

1. Mold

Since basements are below ground level, they are already damp environments that are susceptible to mold growth. Add in water that can seep in from the walls and floor, and you have the perfect habitat for mold.

Mold in the basement can dramatically impact the air quality in the entire home, causing significant respiratory issues and headaches.

2. Structural Damage

Although rare, a leaky basement left unchecked can sometimes lead to structural problems. If the soil around the foundation is allowed to become saturated, it can create hydrostatic pressure that can cause cracks and even heave in the basement floor. This type of damage can cost thousands of dollars to repair.

Water can also wear away at the mortar and concrete that comprises the foundation, weakening it over time.

3. Damage to Wiring and Appliances

While protecting a finished basement that serves as a living area from rain is necessary to protect flooring, furnishings, and electronics, even unfinished basements are vulnerable to damage. Unfinished basements often serve as laundry rooms and typically house water heaters and furnaces.

Washers, dryers, and HVAC appliances are not impervious to water and face the threat of water damage. With this in mind, it’s imperative to solve any leaks that may be allowing rainwater to enter to protect these appliances.

How to Prevent Rain Water From Entering Your Basement?

How to stop water from seeping through basement walls

There are several simple and affordable solutions to stopping the flow of rainwater to the basement. In this section, we’ll cover the easy fixes as well as more aggressive measures for preventing rainwater from entering your basement.

1. Clean the Gutters

Often what’s going on below can be attributed to what’s going on above. Gutter and downspouts are there for a reason. They direct water away from home, keeping the soil around the foundation dry and preventing water from seeping into the basement.

When they are clogged or not properly aligned, they can’t do their job. Clean the gutters to make sure water flows to the downspouts and not over the side of the gutter.

Next, check the downspouts. They should empty to a part of the yard that is sloped away from home. If the downspouts empty to any area where water is pooling or running back to the foundation, install gutter extenders to direct the water away from home.

2. Repair cracks and holes

Cracks and holes in the walls or foundation are some of the most common means for rainwater to infiltrate a basement. Use hydraulic cement to seal any visible cracks or holes to keep water out.

Keep in mind that the crack or hole may just be a symptom of a larger problem, so sealing this damage may only provide a temporary fix. It’s possible that pressure created by water collecting around the foundation caused these holes in the first place, so filling them won’t prevent new holes from forming.

With this in mind, be sure to address any issues with grading, clogged gutters, or poorly directed downspouts before repairing the holes or cracks.

3. Improve the Grading Around the Foundation

Homes are designed so that the earth around the foundation slopes away from the house. In some cases, erosion or a poor design can cause the opposite to happen, allowing water to puddle or pool around a foundation.

If clogged gutters are left to their own devices, the impact of the overflowing water hitting the ground can be enough to erode the grading around a home.

To fix the grading, build up dirt around the foundation to create the necessary slope for proper water run-off.

Minor grading can be accomplished by adding topsoil around the foundation to bring the ground level up. For more extensive grading, you’ll likely need to call in professionals as the job can be laborious.

4. Repair and Reseal Window Wells

There are a few ways to handle leaky window wells. If the window well has a drain, it’s likely clogged. Locate it by digging through any gravel that may be at the base of the window well, then remove any clogs that are preventing water from draining out of the well.

If there is no drain and rainwater is falling into the window well, consider purchasing covers to protect the well from the rain.

If rainwater is flowing over the sides of the well from the surrounding yard, then you’ll have to do some grading (see above) to prevent the water from draining toward the well.

5. Install a Basement Drainage System With Pump

If you have a cove joint leak that can’t be fixed with gutter repair or regrading, you may need to install a drainage system. These systems consist of a french drain that runs the length of the floor near the walls.

The drain funnels water into a sump pump basin that then pumps water out of the basement into a drainage area outside the home.

Consider this as a last resort as basement drainage systems typically involve removing part of the floor near the wall. This is a significant renovation that typically requires a basement drainage specialist and is very costly.

6. Add a Dehumidifier

If your basement has minor leaks during a rainstorm that amount to a few gallons of water, then a dehumidifier may be all you need to do the job. A dehumidifier can reduce the moisture content in the air by 50 percent with its ability to remove up to 50 pints of water a day.

A dehumidifier not only prevents moisture from forming due to condensation but also prevents any water that seeps in from lingering. Dryer air is better able to absorb water that seeps into the basement, preventing puddles from remaining in the basement for days or weeks.

While a dehumidifier won’t solve larger flooding issues, it can be an affordable solution for basements that collect smaller amounts of rainwater.

7. Add an Exterior Waterproof Membrane

If the leak persists even after you’ve checked the grading and repaired the gutters and downspouts, then you may need to install a waterproof membrane around the foundation.

A waterproof membrane attaches to the exterior of the foundation wall and serves as a barrier that prevents water from reaching the concrete. The membrane has to be installed well below ground level, so it involves digging up all the soil around the foundation. As this is a costly process that typically costs thousands of dollars, adding an exterior waterproof membrane should only be considered as a last resort.

Does Homeowners Insurance Cover Water Damage From Rain?

Most homeowner’s insurance will cover water damage caused by failing plumbing or appliances such as a burst pipe, leaky water heater, or even an overflowing bathtub.

What isn’t covered by standard home insurance is flooding caused by acts of nature, which would include rain. To cover damage from rainwater, you’ll need to purchase specific flood insurance. Even then, you’ll need to make sure you take out a flood insurance policy that covers BOTH the contents of the home as well a the structure.


Finding rainwater leaking into a basement can be daunting for any homeowner. Although it may be tempting to call in the pros right away, resist the urge.

Trying easy fixes first can save you thousands of dollars in a professional waterproofing system you and your basement may not need. The solution to a leaky basement is often as simple and affordable as cleaning a clogged gutter, extending a downspout, or covering a window well.

Whatever solution you decide to use, don’t turn a blind eye to a leaky basement. Left unchecked, a basement that perpetually leaks can lead to mold growth and even structural damage.

Written By: Yevgen

YevgenI'm a DIY nut, and the founder and chief editor here at Weekend Builds.
This site is a result of my DIY passion, and to share the joys I have experienced fixing, building, and creating things over the years.

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