A leak beneath a concrete slab can be difficult to spot because the plumbing is out of view. The symptoms below can have other causes too, so use them as clues rather than a diagnosis.
Warm or damp flooring
A warm patch may be related to a hot water line, while persistent dampness can have several sources. Note the exact location and whether it changes over time.
Water sounds when fixtures are off
If you hear water movement while taps and appliances are not running, check whether the water meter continues to move, if safe and practical. This observation alone does not locate the leak.
Unexplained water use
A sudden change in a bill or meter reading can be a reason to investigate. Compare similar billing periods and consider irrigation, toilets, and other water uses too.
What to do next
Write down symptoms, dates, and affected rooms. Call a qualified plumbing professional to discuss whether slab leak detection is appropriate. Ask about the diagnostic process and costs before authorizing work.
How can I check safely?
If you suspect an active supply leak, avoid breaking the slab or opening a wall yourself. You can record meter readings, water bill changes and where moisture appears. A professional can explain whether pressure testing or other techniques may help.
A quick checklist before you call
- Where is the suspected leak or unusual water use occurring?
- When did you first notice the issue and has it changed?
- Have you safely checked whether the problem continues when fixtures are not being used?
- What questions do you have about diagnostic methods, scope and cost?
Want to discuss these warning signs?
Call with your location and what you have observed.
This guide is general information, not a diagnosis. For immediate hazards, contact an appropriate emergency professional.