Sneaky Signs of a Slab Leak and What To Do

While any leaking pipe will eventually cause damage to your home if left alone, a slab leak that remains undetected or ignored can cause catastrophic damage to the foundation of your house. Fortunately, a slab leak usually reveals itself early on, if you know where and how to look.

Home Conditions that Can Put You at Risk of Slab Leaks

Your house slab is the poured concrete between the outer foundation walls. During the building of your house, water pipes and sewer pipes are laid out below ground level before the concrete is poured. Everywhere a pipe enters the house it rises vertically above the level of the concrete. These pipes are bound to the slab, imbedded in soil with varying moisture conditions.

Older houses may have galvanized steel water pipes and cast iron sewer pipes, both of which are known to decompose over time and spring leaks. Once a leak has started, the ground under the foundation is compromised and can become a significant liability to the integrity of the house structure over time.

Even in newer homes, slabs move on the earth upon which they sit. Earthquakes or can cause a slab to “float” on the earth, moving up and down or sideways. This motion flexes the plumbing pipes connected to the slab. Over time this motion can cause cracks in the pipes or joints.

Another way slabs move is when subjected to heavy rains. The corners and edges will rise and fall differently than the center. This twisting puts an enormous strain on a plumbing system designed for a rigid environment.

It is always a good idea to have Benjamin Franklin Plumbing perform an annual inspection. This expert multi-point plumbing system test often catches problems before they become costly.

Unexplained Rises in Your Water Bill

Never take your water bill for granted. In the general management of your household, your water consumption should have a seasonal consistency except for any explainable events like having company for an extended period, filling the pool, etc.

If your water consumption rises without cause, you need to check a few things. Note that water consumption is a better indicator than a water bill. Rates fluctuate for external reasons. Water consumption is a household issue, not a slab issue.

  • You may have a toilet that is continually running. Toilet tank malfunctions can lose a surprising amount of water in just a day. They are continuously flushing fresh water. If this is happening, you will hear it, so check the bathrooms.
  • You may have an in-house water supply leak. Check under your sinks. Check your water heater for leaks. Look for water stains or blistering paint on walls and ceilings around plumbing fixtures.

If neither of these points checks out, or if you are not sure, here’s how to find out fast:

  • Turn off all the water outlets in the house and make sure all outside water is shut off too (foundation faucets, sprinkler system, irrigation, etc.)
  • Locate your water meter and notice if the water flow gauge is moving. If it is, that means you are consuming water you aren’t using: you’ve got a leak.

Note that this only applies to leaks in your water line. Sewer line slab leaks are different.

But is it a Slab Leak? Here are the Signs.

  • An unaccounted for spike in water consumption noted on your bill.
  • Water pooling up outside the foundation where water should not be.
  • The floor above the slab is damp or pooling water in areas. Some slab leaks are forced up around the outside of pipes that penetrate the concrete layer.
  • Rises or warps on the floor surface.
  • Unexplained dank smell or mold/mildew. Damp drywall or carpet will quickly develop these issues. Damp spots on your carpet, or mold beneath the carpet.
  • Unexplained low water pressure. First check that it is happening throughout the house and not just at one clogged fixture (if so, clean the showerhead or faucet filters). If the slab leak is affecting the water pressure, you likely have a plumbing emergency and should call Benjamin Franklin Plumbing immediately.
  • Your water heater is continuously running. The line out of the heater is leaking and causing the tank to need to fill, requiring constant heating. You may experience running out of hot water much faster than usual.
  • You notice cracks in the floor or concrete. This is a sign that under-slab erosion is progressing and stressing the concrete beyond its ability to flex.
    What About a Sewer Pipe Slab Leak?
    The concrete slab lies over a portion of the sewer line that runs out through the foundation and into the main sewer line. When the sewer line pipe has been compromised by cracks, decomposition or breaks, the wastewater can erode the ground under the slab, causing cracks and possibly precipitation water pipe leaks as well. You may notice a septic smell or notice grass growing thicker where the wastewater is leaking into the ground. Eventually, the leak will develop a clog either from soil or roots entering the line.

How Do I Fix a Slab Leak?

A slab leak is not a DIY project. The integrity of your house is the issue, and it needs to be addressed by a professional plumbing service. You need the level of experience our expert team of technicians provides at Benjamin Franklin. Our investigation into the problem could save you money. We will evaluate:

  • Is it a slab leak? There may be other causes.
  • The location of a leak affecting the slab.
  • Determine if the leak can be fixed by going down through the slab and doing a spot repair or by excavating and running a new line. Both have their pros and cons and are dependent on what has gone wrong.
  • Fix any damage to the slab or the ground beneath the slab affected by erosion.