7 Signs You Have a Slab Leak

2017 Mar 03
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Early detection is super important when it comes to a leak in your home’s slab foundation. If left undetected and unrepaired, a slab leak can eventually lead to thousands of dollars in water and structural damage to your home.

So what should you be on the lookout for? Well, 7 signs that you have a slab leak include:

  • A sudden, unexplained spike in water bills
  • Water pooling where it shouldn’t
  • Damp carpet or warped hard flooring
  • Mold or mildew (visible or just the smell)
  • A decrease in water pressure
  • A hot water heater that’s constantly running
  • Areas of the floor that are suddenly hot

We’ll explain each of these in detail and show you one foolproof way to test for a leak in your home’s plumbing.

See the signs and need a professional plumber’s help ASAP? Just contact us, we respond right away for fast slab leak repairs.

Sign #1: A spike in your water bill

Any leak in your home’s plumbing comes with higher-than-normal water bills. That’s because a leak allows water to run 24/7 instead of only running when you’re actually using water.

So, if you get a water bill that’s excessively higher than past months and there’s no explanation for the spike (such as increased water usage due to house guests), you may have a slab leak.

Source

Sign #2: Water pooling where it shouldn’t

If you have a slab leak, water will accumulate under the foundation until it finds a way to escape. Be on the lookout for water that seems to be pouring out from the slab foundation on the outside of the home. If there are no hoses in the vicinity or any other explanation for water in that area, you most likely have a slab leak.

Water can also pool inside your home, such as on your kitchen or bathroom floor. If you can determine that any nearby water appliances aren’t leaking, it could very well be water pushing its way up from a leak in the slab foundation.

Sign #3: Damp carpet or warped hard flooring

When you have a leak in the slab foundation of your home, that water accumulates and sometimes has nowhere to go but up. And eventually that water will reach your flooring and cause visible damage.

If you have carpet throughout your home, keep an eye out for damp areas or spots that suddenly appear darker. If you have hard flooring, keep an eye out for warping of any kind.

Sign #4: Mold or mildew

If water from a slab leak makes its way into your flooring, you’ll soon have mold and mildew growing on and under your carpet. It’s also possible that some water will be absorbed by your home’s walls. And damp drywall usually leads to mold in your walls.

While mold growing under your carpets and inside your walls may not be visible, you’ll definitely smell it. So if you notice a sudden musty, mildew smell coming from your carpet or walls, check for other signs of a slab leak.

Sign #5: A decrease in water pressure

When water is constantly escaping your pipes via a leak, that means less water is able to travel to your faucets and water fixtures when you need it.

So if you notice a decrease in water pressure, especially when no other water fixtures are in use, you could have a slab leak that’s “stealing” your water pressure.

Sign #6: A hot water heater that’s constantly running

If you have a hot water leak underneath the slab foundation of your home, it’s basically the same as leaving a hot water faucet on 24/7, which also means your hot water heater needs to work 24/7 to keep up.

So if your water heater is suddenly working non-stop, there’s a very good chance that you have a leak somewhere in your home’s plumbing.

Sign #7: Areas of the floor that are suddenly hot

If the leak under the slab foundation of your home is on the hot water side, that hot water will eventually heat up the concrete directly above it. And with time, the heat from the concrete will transfer to your flooring.

If you have carpet, hot areas are almost impossible to detect but if you have tile, hardwood flooring or linoleum, you’ll easily detect hot spots from a hot water slab leak. Keep an eye out for pets that suddenly lay in a specific spot on cold days and check if the floor there is warmer than the surrounding areas.

How to test for a leak in your home’s plumbing

Seen a few of the signs above but want to check for a leak yourself before calling in a professional? Just follow the steps below.

Step 1: Turn off all water appliances and make sure there is no water running anywhere in your home.

Step 2:  Go outside and locate your water meter. Water meters are usually located outside near the driveway or along the boundary of your property. It’s usually marked by a plastic or metal covering labeled “Water Meter”.

Step 3: Remove the cover. Usually this can be done by simply lifting open the cover but you may need to use a screwdriver to pry the lid open.

Step 4: Depending on the water meter you have, you can check the numbers or triangle to check for a leak.

If your water meter looks like the one below, check the red triangle to the left. Is it moving? If it’s rotating, that means water is still flowing through your home’s pipes and you have a leak.

If your water meter looks like the one below, check the numbers at the bottom. If the numbers are going up, you have a leak somewhere. Note: Depending on how large the leak is, you may need to record the number then recheck after 30 minutes to see if the numbers go up.


If after this test you’ve determined that you have a leak, keep in mind that it doesn’t necessarily mean that the leak is located under the slab foundation of your home. It just means you have a leak somewhere in your home’s plumbing.

A professional can pinpoint the location of the leak and give a quote for the leak repair.

Have a slab leak and need it repaired? Get a quote from an AZ plumber

If you think you have a leak somewhere in your home’s plumbing, don’t wait to get it fixed.

Contact us today, we’ll send over a professional to locate the leak and give you an estimate to repair the leak.

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