How to Fix a Leaky Basement

A basement is a must-have for many homeowners, whether they want a finished living space or an unfinished storage area. However, because basements are built below ground level, they are prone to leaks. This guide explains how to fix a leaky basement based on the cause and extent of the issue.

Why Is My Basement Leaking?

If your basement has leaked, you will need to determine the cause. Here are the most common reasons for a leaky basement:

• Excessive rainfall

• Clogged gutters and downspouts

• Poor drainage causing rainwater to put pressure on the basement walls

• Improper yard slopes

• Untreated cracks and holes in the basement wall

• Broken drain system or sump pump

• Leaking appliances

How Much Does It Cost to Fix a Leaky Basement?

The cost to fix a leaky basement will depend on the cause of the leak. Basement waterproofing costs between $2,460 and $8,190, with the total cost depending on the size and condition of your basement, the type of sealant used, and local labor costs. If your basement experiences frequent and extensive leaks or mold is present, you can expect your costs to increase significantly.

How to Fix a Leaky Basement

Fixing a leaky basement can be a simple task or a complex and lengthy project that requires the expertise of a professional. Here’s how to fix a leaky basement, depending on the cause.

Check Your Gutters and Downspouts

Surprisingly, your leaky basement could be caused by a problem with your home’s gutter system or downspouts. Clogged or cracked gutters will overflow or leak, directing rainwater toward your home’s foundation rather than away from it. And short downspouts can deposit water right next to your basement as well.

Clearing your clogged gutters and replacing any damaged sections can make a huge difference to your basement. Installing downspout extenders helps direct water further away from your home, thereby decreasing the chances of a basement leak. 

Seal Foundation Cracks

Cracks in your foundation walls aren’t necessarily a sign of structural damage, but they can let water leak into your basement during times of heavy rainfall. Small cracks measuring less than ⅛ inch can be repaired using an interior sealant or hydraulic cement, but repairing larger cracks is a job best left to a local foundation repair professional.

On average, foundation repair costs $5,170. However, if your foundation shows signs of significant structural damage, you may face costs of $35,000 and up. Addressing minor cracks as soon as you notice them can prevent further damage and save you thousands of dollars in the long run.

Regrade Your Yard

The slope of your yard can determine whether your basement is prone to leaks. If your yard is graded toward the house, water will drain toward the foundation rather than away from it. This then causes hydrostatic pressure, when excessive groundwater exerts force against the foundation, putting pressure on the basement walls. If your basement has any cracks or gaps, the pressure will cause water to leak through them.

Regrading your yard so it slopes away from your house can help alleviate this pressure and decrease the chances of a basement leak. The typical cost to regrade or level a yard ranges from $1,030 to $3,340. 

Waterproof the Basement Walls

Waterproofing your basement walls can help prevent leaks and keep your basement drier. Depending on the cause of your basement leaks, a contractor might recommend exterior or interior waterproofing.

Exterior basement waterproofing involves digging around the home’s foundation and installing a dampproofing membrane. This is a labor-intensive process that costs an average of $7,000, but it can save you a significant amount of money and hassle in the future.

Waterproofing the interior basement walls is significantly less expensive, at around $3,000, primarily because no excavation work is involved. A pro can install a vapor barrier for $1,500 to $3,000, or they might recommend waterproofing paint for $1 to $8 per square foot.

Install a Drainage System

A drainage system can help direct water away from your home, preventing basement leaks. An interior French drain can help keep leak-prone basements from flooding. This type of drain is installed around the basement walls, allowing water to drain outside the home rather than inside. The cost to install a French drain ranges from $500 to $18,000, depending on the type of French drain selected and its location.

Install a Sump Pump

A sump pump is another type of drainage system that prevents water from leaking into your basement. This type of system consists of a tank dug into the lowest part of your basement and a drain system that directs water from around the foundation into the tank, where it is then removed via an exterior discharge pipe into a storm drain or a dry well.

Installing a sump pump costs between $1,200 and $1,500, making it an affordable way of keeping water from leaking into your basement. The exact project cost depends on the location of the sump pump and the type of system chosen. Professionals often recommend installing a battery backup to ensure your sump pump continues to function even during a power outage.

Check the Appliances

If you have appliances in your basement that use water, such as a washer or water heater, check to see if they are leaking and causing water to pool in your basement. Washing machine repair costs $125 to $450; however, if the repairs will cost more than 50% of the replacement cost, it’s usually better to buy a new one. The cost to repair a water heater ranges from $221 to $985.

Tips for Dealing With a Leaky Basement

Follow these tips to clean up the space and prevent future water leaks from occurring:

• Don’t ignore cracks or holes. Even a small crack in your basement wall is capable of leaking if exposed to hydrostatic pressure. And left untreated, these small holes and cracks can become much larger.

• Locate the source of the leak. The first thing to do when you notice water in your basement is to determine where it’s coming from. Once you find the source of the leak, you can determine the proper steps to stop future leaks.

• Mitigate the damage. If the leak causes water damage in your basement, start cleaning it up as soon as possible to mitigate the damage. If you don’t, your basement could become infested with mold.

• Use fans and dehumidifiers to remove moisture. After a leak, your basement will be humid. Dry it out using fans and use a dehumidifier to remove moisture from the air, preventing mold growth.

• Install a leak detector. When the system detects water, it will produce a sound and send an alert to your phone, allowing you to address the issue before it worsens.

DIY vs. Hiring a Pro

The choice between fixing a leaky basement yourself and hiring a pro will depend on the cause of the issue. If your basement leaks because your gutters are clogged or your downspouts are too short, you can often address the problem yourself. However, extensive leaking caused by a poorly graded yard, inadequate drainage, or cracks in the foundation requires the expertise of a professional. Knowing who to call for water in your basement will save you time if and when the issue arises.

Hiring a professional basement waterproofing contractor near you will ensure the leaky basement is fixed by addressing the root cause rather than applying temporary fixes. A pro will inspect your basement for cracks, holes, and bowed walls and recommend the proper fixes. They will then waterproof your basement properly to prevent future leaks, leaving your basement dry and comfortable.