Article
Quick Answer: The most common signs of a hidden water leak are an unexplained rise in your water bill, a water meter that keeps moving when nothing is using water, damp or warm spots on floors or walls, a musty smell, and the sound of running water when every fixture is off.
The Signs, One at a Time
- An unexplained increase in your water bill. If your usage habits haven’t changed but your bill has climbed, that’s one of the most reliable early indicators of a leak. See our full breakdown of high water bills and leaks.
- A water meter that won’t stop moving. Turn off every fixture and appliance that uses water, then check your meter. If it’s still moving, water is going somewhere it shouldn’t.
- Damp, soft, or discolored spots on floors, walls, or ceilings. These often point to a leak in the plumbing running through or under that area, including a possible slab leak.
- A warm spot on the floor. This is a classic (though not definitive) sign of a leaking hot-water line running beneath a concrete slab.
- A musty or mildew smell with no obvious source — moisture trapped behind a wall or under flooring often produces this before any visible damage appears.
- The sound of running water when every fixture in the property is confirmed off.
- Unexplained wet or unusually lush patches in the yard, especially ones that stay wet regardless of weather — a strong sign of an underground leak.
- Reduced water pressure across the property, which can indicate water escaping the system before it reaches your fixtures.
- Foundation cracks or shifting that appear without another clear cause, which can be a longer-term effect of a slab leak that’s gone unaddressed.
One Sign Is a Clue. Multiple Signs Are a Pattern.
Any one of these alone isn’t proof of a leak — a warm spot could just be sunlight, a smell could be seasonal humidity. But when two or more show up together, especially alongside a rising water bill, it’s worth having a professional inspection before guessing further.
What to Do Next
If you’re seeing any combination of these signs, the next step is a non-invasive diagnostic inspection — not opening up walls or flooring. Call (470) 454-5051 to describe what you’re noticing, and we’ll help you figure out what kind of testing makes sense.
FAQ
What's the most reliable early sign of a hidden leak?
An unexplained increase in your water bill combined with a water meter that keeps moving when all water use is off is one of the most reliable combinations.
Does a warm spot on the floor always mean a slab leak?
Not always, but it’s a common sign of one. A warm spot can be associated with a leaking hot-water line beneath a concrete slab, and it’s worth having tested rather than assumed either way.
I only have one of these signs. Should I still get it checked?
It’s a judgment call, but a rising water bill or a moving meter with no water in use are both worth investigating on their own, even without other symptoms present.