If your home has a concrete slab foundation, the bulk of your home’s plumbing system likely runs through that slab. The concrete protects the pipes from damage, but it also makes them difficult to access if there’s a problem. 

When one of the pipes cracks or erodes, you may have a slab leak on your hands. This can threaten the structural stability of your home. Although slab leaks are costly to repair, they’re even costlier to ignore. In this guide, learn more about the cost of slab leak repair and how to protect your home’s foundation.

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What Is a Slab Leak?

Your plumbing pipes are likely beneath or inside of your home’s concrete slab foundation. If any of these pipes break, crack, or erode, a water leak will result. Here are the most common causes of slab leaks:

• Corrosion: Cast iron and other metal pipes can erode and rust over time.
• Excessive water temperature and pressure: The more stress on the pipe, the more quickly it will deteriorate.
• Manufacturing defects: Plastic and PEX pipes resist corrosion, but weak points in the material can lead to breaks and cracks.
• Pressure on the pipes: Pressure can crack the pipes as a slab foundation settles, sinks, or cracks.
• Water chemistry: Over time, hard or acidic water will damage some pipe materials faster than others.

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What Is the Cost of Slab Leak Repair?

The average cost of slab leak repair is $2,300.* Depending on the extent of the problem, repairs may cost as little as $630 or as much as $4,400 or more. The location of the leak is the most relevant factor to cost because this determines how difficult it is to access and repair the leak. The cost for this type of project is difficult to predict before you’ve had the slab inspected.

*Cost figures in this article were sourced from HomeAdvisor and internal data.

Here’s a breakdown of the average cost by repair type:

Learn more about each cost factor in the dropdown sections below:

Slab Leak Detection

While you might detect signs of a leak on your own, finding the leak’s source typically requires a professional. An inspector may need to feed a camera into the pipes to pinpoint the source. Detection alone can cost $150–$600, depending on how hard it is to find the leak. At this point, you will get a better idea of the extent of the problem.

Under-Slab Plumbing Repair

Slab leaks are caused by broken pipes under or inside the slab. The cost to fix the leak will depend on the accessibility of the damaged pipe. For example, there may be tunneling under the slab. Some slabs contain ready-made access holes. In some instances, the plumber may need to crack open the slab. This type of repair can cost anywhere from $500–$4,000.

Main Waterline Repairs

Your home’s water main is the pipe through which water comes into your house. Main waterline repair will typically cost between $300–$1,400. The price may be higher if the line is difficult to access.

Foundation Repair

If plumbers need to break into your home’s concrete slab foundation to make repairs, you need to spend the money to repair the foundation when the job is done. Patching small holes in concrete can cost as little as a few hundred dollars. Larger concrete pours, on the other hand, cost from $2,000–$7,500 if you require a separate crew to lay new reinforcements and finish the slab.

Broken Piping Repair

There are several ways to repair a leaking pipe inside a concrete slab. If the leak is small, the plumber may be able to apply epoxy—a resin that seals small gaps and leaks—and will charge around $200. For larger leaks, some or all of the pipe will need to be replaced at a price of up to $2,000. In some cases, plumbers can install a trenchless pipe lining to fix a leak without needing to break into the slab. Though this method is less invasive, it’s no less expensive.

Rerouting Pipes

If multiple pipes are broken or leaking, it may be more cost-effective to reroute plumbing pipes around the slab. The plumber will cap off the old lines and install new pipes, often running them above the house through the attic. This repiping typically costs at least $1,500 and can cost as much as $15,000.

Total Slab Replacement

The most drastic plumbing repair for a slab leak consists of demolishing the old slab, repairing the pipes, and pouring an entirely new foundation. This is necessary in the case of severe leaks, a sunken or broken slab, or a very old plumbing system. 

You’ll need to hire concrete contractors to break up the existing slab with a jackhammer and then remove and dispose of the pieces. After a plumber repairs the water pipes, the concrete contractors will return to pour the new slab. Pouring the slab alone costs $3,600 to $8,000, or about $6 per cubic foot of concrete. Pipe repair will cost extra.

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How Much Are Slab Leak Repair Labor Costs?

Licensed plumbers tend to charge between $45 and $200 per hour based on a number of factors, including the experience level of the plumber and the cost of living in your area. Since this is an hourly rate, anything that makes the job take longer will increase the total cost of the project. Multiple leaks, severe leaks, and difficult-to-access leaks will all come with additional costs.

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How Do You Prevent a Slab Leak?

While there’s no such thing as an indestructible slab or pipe, there are some steps you can take to reduce the likelihood of a slab leak:

• Avoid using chemical drain cleaners, which may hasten pipe erosion.
• Call a plumber at the first sign of a potential slab leak.
• Keep tree root systems away from your home’s foundation.
• Keep your home’s water pressure between 50 and 75 psi (pounds per square inch). Never exceed 80 psi.
• Schedule an annual plumbing inspection to catch problems early, especially if you own an old home with older pipes.

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How Do You Detect a Slab Leak?

Here are some of the warning signs that you could have a slab leak:

• Mold, mildew, or water damage on floors or under carpet
• Sounds of running water when the water is turned off
• Standing water or spongy ground around the foundation
• Sudden increases in your water bill
• Sustained low water pressure in faucets or showers
• Visible cracks in the foundation
• Warm spots on the floor from a broken hot water line
• Warped or cracked floorboards or baseboards

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Should You DIY vs. Professional Slab Leak Repair?

Because slab leak repair costs are so high, some homeowners may wonder if they can perform the repairs themselves. Unfortunately, slab repair isn’t a DIY project.

Professional Slab Leak Repair

A professional will have the necessary tools and training to do the job from start to finish. Here are the typical steps in the process:

1. You call a professional plumber, who will perform an inspection of your plumbing system to determine the source of the leak.
2. The plumber will discuss your options with you, including the best way to access and fix the leak.
3. If necessary, a contractor will break open the concrete slab so the plumber can perform the repairs.
4. When the plumber is finished, a concrete contractor will patch the slab. If the damage is extensive, the contractor will pour a partial or full replacement and finish the concrete.
5. Alternatively, a plumber may be able to complete a trenchless repair by inserting new pipe linings into the existing pipes.

DIY Slab Leak Repair

The entire weight of your home rests on your concrete slab foundation. It’s not a good idea to attempt to crack into or tunnel under it yourself. Trying to access your pipes without the right tools or knowledge can cause further serious damage. You could weaken the foundation or inadvertently put more stress on other pipes, causing more leaks. Although the cost of a slab leak repair is high, it’s worth hiring a professional to do the job.

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Our Conclusion

The national average cost of a slab leak is $2,300, but it may cost much less or much more depending on the cause and extent of the problem. Because this is a complicated repair job, you must hire a licensed plumber to do the work. We recommend getting estimates from at least three local professionals before making your choice. Ensure that the plumber you pick is licensed, bonded, and insured before they get into your plumbing system.

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FAQ About Slab Leak Repair

Does homeowners insurance cover slab leak repairs?

Homeowners insurance typically covers slab leak repairs if the leak is a result of a covered incident. For example, if your homeowners insurance policy covers earthquake damage and a leak develops after an earthquake, the leak will be covered. Slab leak repair won’t be covered as part of general home maintenance.

How long does it take to fix a slab leak?

It typically takes between one and three days to fix a slab leak. It may take more or less time depending on the severity of the problem and the location of the leak.

Is a slab leak an emergency?

A slab leak is considered an emergency plumbing issue because a leak can cause serious damage to a home’s foundation. You should call a plumber as soon as you suspect a slab leak.

What are the signs of a slab leak?

The signs of a slab leak in your home’s foundation include the following:

• Low water pressure
• Mold, mildew, or wet spots
• Sound of running water
• Spike in your water bill
• Warped floorboards

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