The Complete Guide to Repairing Water Leaks Under Your Slab (2024)

We can’t live without water, but finding water where you don’t want it can signal the beginning of expensive trouble for a homeowner. This guide will help you figure out what to do about under-slab leaks on your property and how to get the right kind of help when you need it.

When we think of water, we naturally think of pipes, so your first impulse might be to call a plumber. They know their way around pipes for sure, but plumbers don’t work with slabs for a living. For this reason, a plumber will often overcharge you for diagnosis and repair because they don’t have the right equipment or expertise to deal with the structural part of the problem.

Concrete experts who are qualified to perform complex slab and foundation repairs can efficiently tunnel beneath a structure and get to the source of the trouble with minimal disruption to your property. It’s the right place to start if you see warning signs of an under-slab water leak.

What causes under-slab leaks?

Homes are built to last, and we tend to think of them as immovable objects. In fact, houses and the earth beneath them are constantly moving, expanding and contracting with the seasons and all sorts of other natural forces. Over time, this repetitive motion can put a strain on vulnerable materials – especially pipes that pass under or through shifting concrete.

Here are 7 common factors that could lead to under-slab leaks:

  1. Natural expansion and contraction of soil and building materials
  2. Improper installation of water bearing pipes
  3. Hydrostatic pressure due to improperly managed ground water buildup
  4. Seismic activity in areas prone to earthquakes
  5. Local water chemistry that causes certain pipes to wear out from the inside
  6. Chemical reactions between metal piping and metallic elements in the soil
  7. Deterioration of pipe materials due to corrosion or abrasion

Older copper or galvanized metal pipes can be more vulnerable to the kind of deterioration that causes under-slab leaks. For this reason, some homeowners replace them with modern cross-linked polyethylene piping materials as a long-term preventive measure, but complete replacement can be an expensive undertaking.

What are the top warning signs of an under-slab leak?

The Complete Guide to Repairing Water Leaks Under Your Slab (1)In some cases, the damage from an under-slab water leak may only be cosmetic (especially if you catch it early) and may be fairly inexpensive to repair. By their very nature, other kinds of under-slab leaks can remain hidden for a long time and may cause serious structural damage.

Fortunately, if you inspect your home on a regular basis (including spaces that you rarely visit during your family’s everyday living routine), many signs of under-slab leaks are relatively easy to spot. Here are 8 of the most common ones:

  1. Warm spots in a floor above hot water lines
  2. Flooring materials that begin to bulge, buckle, crack or separate
  3. Moisture or signs of mold or mildew in carpeting
  4. Odd or musty smells coming from floors or walls
  5. Wet spots or stains in basem*nt floors
  6. Sudden spikes in your water bill that can’t be easily explained
  7. The sound of running water beneath your home
  8. Changes in water pressure in faucets or showers

If you notice any of these things, it’s important to get a professional inspection as soon as possible. Foundation damage can spread quickly when structural components (or the soil holding them up) become compromised by accumulating water.

How does the under-slab leak repair process work?

Foundation repair specialists who are experienced with concrete slabs know how to search for and isolate the source of hidden water leaks. They use a combination of specialized visual and electronic techniques (such as remote cameras or listening devices), plus evaluation of the external traces that water leaks can leave based on extensive professional training.

Once the source of the leak has been confirmed, a reputable repair technician will discuss your options with you and expose the leaky section of pipe using the least invasive method possible. A qualified concrete repair company is equipped to tunnel underneath your structure in a targeted way that protects the rest of your property. They will purge the faulty section of pipe, replace it with new material and test the line to ensure that the leak has been fixed.

Qualified foundation repair specialists have the experience and equipment to tunnel as far as 100 feet beneath an affected concrete slab once they’ve confirmed the location of the leak. Not only is this approach far less invasive and destructive than jackhammering out portions of the slab, it also allows you and your family to stay in your home while repairs are underway. This method creates less noise, dirt and dust, maintains the structural integrity of your home, and also helps to protect your remaining undamaged flooring.

In some cases, smaller, localized leaks can be repaired by pouring an epoxy material into the affected line. This seals the leak without blocking the surrounding pipe and can be a relatively affordable (and time-saving) alternative to more complex and disruptive repair methods.

In other instances, it may be possible to repair the leak with a method called “cast in place piping.” This process involves remotely cleaning the original pipe, flushing out debris and then forcing a flexible, epoxy-coated lining through the length of the line. The layer of epoxy hardens between the liner and the original pipe wall, forming a newly sealed line within a line.

As we mentioned earlier, these are complex repairs, especially if the leaky pipe is part of your home’s sewage system. In this case there are specialized sanitation and health measures you need to deal with in addition to ordinary water damage. It may be tempting to start ripping up flooring or carpeting, but having the right professional help from the beginning is very important and will likely be more affordable than you think.

Here are some good times to perform slab leak detection:

  • Before undergoing foundation repair
  • After foundation work
  • At the sign of foundation problems
  • If you discover excessively moist areas underneath floor coverings
  • If you hear running water when water should not be in use (usually emanating from the bathroom)
  • Unusually high water bills
  • Before purchasing a new home
  • At least once annually (in climates prone to foundation cracks)

What is a sewer clean out?

A sewer clean out is a plumbing pipe, typically sticking out of the ground that has a removable plug and is found in the main sewer line. This pipe allows plumbers to clear out a blockage which may accumulate in the system and can also be used as an entry point during the slab leak detection phase.

What to expect from a foundation and slab repair professional

Water leaks of any kind can be a huge worry for a property owner. When they’re happening inside or underneath the concrete in your home, you have to think about more than just the pipes. In situations like these you need a qualified foundation repair specialist on your side who will be able to give you the straight story on all the structural implications and the repair options that are best for your situation.

Reputable foundation and slab repair professionals will perform a complete inspection, often and low or no cost to you. They’ll follow up with an honest evaluation of your situation and give you a transparent explanation of your repair options and what they will cost. Talk with more than one company, check their reviews and reputation and ask for references.

Once you’ve chosen the repair partner you want to work with, you deserve the assurance that they will treat you and your home with respect. The right company will do all they can to contain the repair area as much as possible and put preventive measures in place to protect the rest of the house, your belongings (and most importantly, your family) until everything is back in order.

Here’s an important side note to consider. Many homeowners mistakenly assume that repair costs for under-slab leaks are automatically covered by their homeowner’s insurance policy. While some insurers may reimburse for an event like this, coverages and limits vary widely from company to company and from policy to policy. Many homeowners don’t know that this coverage might be optional and excluded at the time of purchase. You should confirm your specific coverages with your agent.

Choose a repair specialist that puts your needs first

The Complete Guide to Repairing Water Leaks Under Your Slab (2)The reason Olshan exists is to bring value and confidence to property owners like you no matter what your immediate repair situation might be. Your home is one of the biggest lifetime investments you’ll ever make, and we’re here to help you protect that investment. Our trained technicians know how to diagnose and repair under-slab water leaks and will help you find the solution that’s best for you and for your budget.

Thousands of property owners in over a dozen states have trusted us to restore and repair foundations, slabs, basem*nts and crawl spaces and more since 1933. The secret is simple. Integrity is a pillar of our business and we treat your family as we would treat our own.

Olshan is one of the most experienced and respected contractors in the foundation repair and waterproofing industry. We’re also one of the largest. That means we’re big enough to bring you all the right resources, but small enough to stay responsive to your needs as a customer.

To learn more about under-slab leaks or to book a no-cost, no-obligation consult with a qualified repair expert, we invite you to contact your local Olshan office team.

The Complete Guide to Repairing Water Leaks Under Your Slab (2024)

FAQs

How much does it cost to fix a broken pipe under a slab? ›

The average slab leak repair cost, which includes having a professional come to your home to find a leak, ranges from $150 to $400, depending on how difficult it is to determine where the leak is. On top of that, the cost to rip out concrete and repair the damage to the pipe can cost around $2,000.

Does homeowners insurance cover broken pipes under slab? ›

Though homeowners insurance covers slab leaks and water damage caused by burst pipes, it typically won't cover the cost to fix the broken pipes. If your pipes are broken but there isn't any actual damage to your slab, you'll likely have to pay the cost of any repairs out of pocket.

How to stop water leakage from slabs? ›

What Can You Do To Prevent Slab Leaks
  1. Avoid Using Too Much Water Pressure. While many people love high water pressure, excessive water pressure can cause pipes to weaken and rupture. ...
  2. Take Action Against Hard Water. Hard water can also have a negative impact on pipes. ...
  3. Avoid Chemical Drain Cleaners.

How do you stop water seeping under a slab floor? ›

The only way to stop water from coming up through your foundation slab is by installing a drain tile system, vapor barrier, and sump pump. Installing a vapor barrier will counter moisture seepage – A vapor barrier is a thin (10 to 20-mil thick) sheet of polyethylene that's placed along your foundation walls.

What happens if water gets under a concrete slab? ›

Water underneath concrete can soften or wash away the supporting soils and cause the slab to settle or crack. If the cracked slab is near your home, it can direct surface water toward your home and cause foundation settlement or soil washout on a much greater scale.

How does a plumber detect a slab leak? ›

One of the most effective tools plumbers use to detect slab leaks is an acoustic listening device. These devices are designed to amplify the sound of water flowing through pipes, making it easier to pinpoint the exact location of a leak.

How long does plumbing last in a slab? ›

If your home is undergoing a renovation or remodel, you may want to consider repiping a house built on a slab during the construction project. It's easier to replace pipes inside walls before hanging drywall. Brass and copper pipes tend to last 80 to 100 years. Galvanized steel may only last 70 to 80 years.

How long does it take to fix a broken pipe underground? ›

It can take anywhere from a few hours to a few days to have a water main break completely repaired. The amount of time it takes to fix a water main depends on the size of the break, where the break is located, and what type of environment it is in.

Can pipes burst under slab? ›

Most of the time, slab leaks can go unnoticed by homeowners. A pipe may burst anytime and begin to leak water into the surrounding soil. The soil will then begin to shift, compromising the overall foundation of the home as the concrete cracks.

Does home insurance cover foundation water leaks? ›

Most homeowners policies will cover foundation repair as long as the damage was caused by a covered event. Issues such as neglect or lack of maintenance can result in damage that won't be covered, so it's important to understand your responsibilities.

How do you know if you have a broken pipe under the house? ›

Unpleasant Odors

A burst pipe can lead to standing water in hidden spaces, like the walls or under the floor. Stagnant water can create a foul smell that permeates your home. If you feel a musty or mildew-like odor but can't locate the source, you may have a hidden water leak caused by a burst pipe.

How to repair a water leak under a slab? ›

A professional uses a jackhammer to break a section of the concrete slab where the leak is located. After breaking the concrete slab, the pro digs with a shovel or spade until they access the pipe. From there, the pipe is repaired or replaced. Once fixed, any dirt that was removed from the ground goes back in.

How long can a slab leak go undetected? ›

A slab leak can go undetected for days, weeks, or even months. A large leak or ruptured pipe can cause immediate water damage that's difficult to overlook, but smaller leaks can be no more than a drip, making them difficult to detect.

How do you waterproof under a slab? ›

Under-slab waterproofing has some very unique challenges. There are really just two options: either put a sheet/rolled waterproofing membrane under the the slab, or use chemical admixtures such as Xypex and Concur to waterproof the concrete and block vapor transmission.

How do you waterproof under a concrete slab? ›

Under-slab waterproofing has some very unique challenges. There are really just two options: either put a sheet/rolled waterproofing membrane under the the slab, or use chemical admixtures such as Xypex and Concur to waterproof the concrete and block vapor transmission.

How do you fix water under foundation? ›

Install A Submersible Sump Pump

This is the best remedy for water ponding due to a burst pipe or flooding. Anytime water gets into the crawl space, the sump pump actuates automatically and starts ejecting the water.

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