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Why Do Slab Leaks Happen?

Why do Slab Leaks Happen?

Slab leaks are common in areas where soil has been moved. Movement can happen from erosion, earthquakes, and even high water pressure. During a slab leak, the pipes inside or beneath a home’s slab foundation begin to leak.

At first, leaks are small and may go unnoticed. However, they worsen over time leading to significant damage and costly repairs. If left, they can wreck the soil under your home, causing your foundation to become uneven and, in worst case scenarios, slowly sink your home into the ground.

Slab foundations are popular for Southern California homeowners.
Prevent your home from suffering this damage by learning why do slab leaks happen and what you can do about them.

What Is a Slab Leak?

Houses are built on a concrete slab. Water supply lines and drain lines are often embedded into a concrete slab to make construction more economical.

Over time the pipes beneath the property can become corroded or damaged. The damaged pipes will leak water. They’ll start with a trickle, then onto a larger leak if left untreated. The surrounding soil can soak up that moisture and unsettle the ground, which becomes unstable, and the concrete foundation will weaken and split.

If you don’t fix slab leak quickly, the foundation of your home can move, crack, or start to sink. The flooring and walls in the home can split or collapse, creating much larger issues than a small leak.

Signs You Have a Slab Leak

Cracked concrete can be a sign of a slab leak.
Many homeowners are unaware of the possibility of slab leaks until it’s too late. Slow leaks can take years, and homeowners may not notice until the damage is significant.

Here are some signs for slab leak detection:

  • Suddenly high water bills
  • The sound of running water with no open taps
  • Cracks in the foundation
  • Discolored or damp floor coverings
  • Warm or damp spots on floors
  • A bad smell from the floor or walls
  • Uneven growth in the lawn
  • A visible shift in the soil around the home

If you have one or more of these signs in your home, it’s important to contact professionals to see if you’re dealing with a slab leak.

Why Do Slab Leaks Happen?

Slab leaks can happen for several reasons, including:

Bad Construction

One of the most common causes of slab leaks is improperly installed or poor-quality pipes. Water pipes that are kinked, bent, or dented during installation make them weak at different points.

Bad construction is a reason why slab leaks happen.
Over time, the weak areas spring a leak, or potentially burst, due to the pressure and wear of the water flowing through them. Copper pipes are at a higher risk of corrosion and damage, but any pipes can spring leaks under the right conditions.

Soil Shifts

Soil shifts, including earthquakes, can affect the pipes and the concrete slab. The vibration in the ground can trigger joints to become loose between pipes, or directly crack, and cause leaks.

But it’s not just earthquakes. The expansive soils that homes are built on absorb water, causing expansion. The soil moves, bending and weakening the plumbing pipes and connections. Then, the slab leak keeps adding water to the ground, exacerbating the soil expansion and increasing the damage.

Earthquakes are a big reason for soil shifts.
In severe cases, the pressure beneath the slab will need somewhere to go, which is typically in a weakened or cracked area of the slab. This can cause wet spots in the floors, but if it’s severe, the floor may erupt and cause a flood in your home.

Poor Water Quality

In cities and suburbs, the water can be very hard and acidic. Typically, hard water has a pH between 1 and 4. Over time, this water can degrade pipes and lead to weaknesses and leaks. Repeated exposure to hard water causes limescale to build up, damaging your pipes.

Some homeowners buy water softeners to combat hard water and remove the harsh minerals, but that has its own downsides. The water softener can prolong the life of the pipes, but if it’s too soft, the pipes will also break down and leak. This is because soft water may leach minerals from the pipes, such as copper or the lead in soldered joints.


Abrasion is a common cause of slab leaks. During the course of regular use, pipes rub against gravel, concrete, nearby pipes, and other hard materials. The friction wears them down over time, creating weak points for holes and leaks.

Pipe breaks are a big reason for slab leaks.
Hot water pipes are at the biggest risk of abrasion. They expand as they heat up, forcing them to rub against concrete or gravel in the soil and increasing the friction.

Fix Your Slab Leak with the Pros

Older homes often have copper or galvanized steel pipes, which are more prone to corrosion and other damage. Extended periods of stress or pressure also contribute to damage and increase the risk of slab leaks.

You must call in a professional to fix a slab leak. Slab leaks affect the foundation of your home.
Regular maintenance of all aspects of your home can keep your plumbing in good condition for longer periods and reduce the risk of unexpected holes or leaks. Also, know the basics of slab leak detection.

Call the professionals at Adeedo if you think you have a slab leak.

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