5 Signs of a Slab Leak in Your Marietta Home
A slab leak rarely announces itself clearly. Here's what to actually watch for if your home was built between the 1970s and late 1990s.
If your Marietta home was built between the 1970s and late 1990s, there's a good chance the copper supply lines running through your slab are now 30 to 50 years old. That's well past the point where pinhole leaks and slab leaks become common, and the tricky part is that a slab leak rarely looks like the dramatic burst pipe most people picture. It's usually quiet, gradual, and easy to miss until it's already caused real damage.
A warm spot on the floor that wasn't there before
If a section of your floor feels noticeably warmer than the rest, especially over a slab foundation, that's often a hot water line leaking underneath it. The escaping hot water warms the surrounding concrete, and that warmth transfers up through flooring, tile, or carpet. It's one of the more reliable early signs precisely because it shows up before any visible water does.
Your water bill jumped and nothing else changed
A slab leak means water is escaping continuously, even when every fixture in the house is off. If your usage habits haven't changed but your bill has climbed noticeably, that's worth investigating rather than assuming it's a billing error. The water meter test is simple: shut off every fixture in the house, then check whether the meter is still moving. If it is, water is going somewhere.
You hear running water with everything off
A hissing or running sound, especially near the floor, with no fixture in use is a fairly direct sign of a pressurized leak somewhere in the system. It's not always loud enough to notice during the day, but it's often audible in a quiet room or at night.
Cracks appearing in flooring or at baseboards
Water escaping under pressure and pooling beneath a slab can, over time, cause visible cracking in tile grout or subtle separation at baseboard trim. This is usually a later-stage sign rather than an early one, which is part of why catching one of the earlier signs matters.
Mold or a musty smell with no obvious source
If moisture has been building under or near a slab for a while, it can eventually show up as a musty odor or even visible mold at a baseboard or wall, without any obvious plumbing symptom pointing to the cause.
You don't need to guess, and you don't need to break up your floor
The good news is that finding a slab leak doesn't require tearing up flooring to search for it. Electronic leak detection, using acoustic equipment to listen for the sound of escaping water and thermal imaging to spot temperature differences in the slab, narrows the leak's location to a small, specific area first. Any concrete that does need to be opened afterward is targeted to that spot, not a guess across the whole floor. Any resulting repair follows the Georgia State Minimum Standard Plumbing Code, based on the International Plumbing Code (IPC).
If you're seeing more than one of these signs, or if you've already had one slab leak repaired and now suspect a second, it's worth having a conversation about whether continuing to repair leak by leak still makes sense, or whether a full repipe has become the more cost-effective option for a home in this age range.
How a slab leak differs from foundation settling
It's worth distinguishing a slab leak from ordinary foundation settling, since the two get confused fairly often. Settling typically shows up as cracks that appear gradually over months or years, often accompanied by doors or windows that stick, without any water-related symptom alongside it. A slab leak, by contrast, almost always comes with at least one of the water-specific signs above, a bill spike, a warm spot, or an audible sound, in addition to or instead of visible cracking. If you're only seeing cracks with no water symptoms at all, that's more likely a foundation question than a plumbing one, though the two aren't mutually exclusive in an older home.
We're happy to help you figure out which situation you're actually dealing with over the phone before you decide who to call first. A quick description of what you're noticing, and roughly how it's changed over time, usually points fairly clearly toward whether you need tracking down a hidden leak or a look at the foundation itself, which we see often in older East Cobb homes.
Don't wait for all five signs before calling
None of these signs need to appear together before it's worth having your system checked. A single, clear sign, especially a water bill spike with no explanation or a warm spot that wasn't there last month, is enough reason to schedule an assessment. Waiting for multiple signs to accumulate usually just means the leak has had more time to cause damage, not that you were being appropriately cautious.
It's also worth mentioning that not every warm spot or water bill increase turns out to be a slab leak. Sometimes the cause is something simpler, a running toilet, an irrigation system leak, or a water heater issue unrelated to the slab. Part of what a proper assessment does is rule out those simpler explanations first, since they're easier and cheaper to fix if that's actually what's going on. The point isn't to assume the worst the moment you notice something unusual, it's to get an accurate answer rather than guessing either way.
Suspect a slab leak?
Electronic leak detection finds it without guessing where to dig.