Leaks & Water Damage
Leak Detection in South Florida: Signs There's a Hidden Leak
Published October 24, 2026 · By the PlumbCove team
Most plumbing leaks in South Florida homes are invisible. The supply lines run under concrete slabs, inside walls, and through attics, and water escaping there can run for months before it stains a ceiling or buckles a floor. By then the water bill has been telling the truth for a while — most homeowners just have not known how to read it.
This guide walks the signs of a hidden leak in the order homeowners usually notice them, then explains how professional leak detection pinpoints a leak under a slab without opening your floor on a guess.
Sign 1: The Water Bill Moved and Your Life Didn't
A sudden, unexplained jump in your water bill — with no extra guests, no pool refill, no irrigation change — is the most common first sign of a hidden leak. Pressurized supply leaks run around the clock, unlike every legitimate use in your home. A pinhole slab leak can lose hundreds of gallons a day, every day, and the meter is the only witness.
Compare the bill to the same month last year, not just last month, to rule out seasonal irrigation. If the jump is real and unexplained, treat it as a leak until proven otherwise — the meter test below takes ten minutes.
Sign 2: The Meter Test — Proof in Ten Minutes
Turn off every water use in the home — no taps, no toilets filling, ice maker and irrigation off. Find your meter (usually near the street) and look at its leak indicator: a small dial, triangle, or digital readout that moves with any flow. If it moves while everything is off, water is going somewhere it should not.
To separate a leak inside the house from one on the service line or irrigation, close the house shutoff valve if you have one and watch again. Still moving points outside or to the irrigation side; stopped points inside. Write down what you found — a detection provider will start from exactly this split.
- ▸Everything off + meter moving = continuous leak somewhere
- ▸Close the house valve: still moving = service line or irrigation side
- ▸No movement = look at intermittent leaks, like a toilet flapper
Signs 3–5: Warm Floors, Sounds, and Smells
A warm or hot spot on tile or wood flooring, in a home where no heating runs, is a classic slab-leak signature: a hot water line leaking under the slab warms the concrete above it. Cold-line leaks show up as damp, cool patches, lifting vinyl, or wood that starts to cup and buckle for no visible reason.
Sound is another tell. With the house quiet, a faint hiss or the sound of running water when nothing is on means water is moving through a pipe somewhere it should not be. And a musty, moldy smell that no cleaning touches — especially near baseboards or inside a closet on an exterior wall — often traces to a slow in-wall leak feeding growth inside the wall cavity.
Signs 6–7: Pressure Changes and Damage Far From Water
A noticeable drop in water pressure throughout the home can mean a significant supply leak diverting flow — though pressure changes have other causes, from a failing regulator to municipal work, so treat this as a supporting sign, not proof on its own.
Finally, the damage that appears far from any pipe: paint bubbling on a wall with no plumbing in it, baseboards separating, cabinets swelling under a sink that 'never leaks when I look.' Water travels along framing, slab edges, and pipe runs. Where damage shows is where water ended up, which is often not where it is escaping.
How Pros Find the Leak Without Guessing
Professional detection layers equipment instead of opening floors. A provider confirms the leak and which system it is on (supply, drain, irrigation, or pool), traces where the lines actually run with electronic locators, listens through the slab with acoustic equipment — pressurized water escaping makes a sound that amplifies at the leak point — and confirms the zone with moisture and thermal scanning.
The deliverable is a marked location and a confidence level, plus repair options: a spot repair at that location, or — when under-slab copper has leaked before — rerouting new lines overhead and abandoning the buried ones. Detection reports also document the leak for your utility: Miami-Dade and Broward commonly grant bill adjustments for repaired leaks when you can show the repair paperwork.
What to Do This Week If You Suspect a Leak
Run the meter test. Photograph your meter reading and the bill that spiked. Check the cheap intermittent causes — a toilet that runs briefly every few minutes is a flapper leak, and it alone can waste a startling amount of water. If the meter moves with everything off, do not wait for visible damage to make the decision for you: under-slab water does not stop, and mold in a warm wall cavity starts fast.
PlumbCove connects South Florida homeowners with independent local plumbing providers who do this detection work. Request a local pro through our leak detection page or call 786-741-7667, and mention your bill timeline and what the meter test showed. Providers are independent businesses; you hire the one you choose, directly.
Rather have a pro look at it?
If the checks above point past the safe DIY line, request a local pro for Leak Detection — or call 786-741-7667. One request, independent local providers, you choose who to hire.