1. The bill went up and nothing else changed
The most reliable early signal, because it is measured. Compare against the same month last year rather than last month - seasonal irrigation confuses month-to-month comparisons.
2. You can hear water when nothing is running
Stand in a quiet house with everything off. Running, hissing or trickling means pressurised water is escaping.
3. A warm or damp patch on the floor
On a slab-on-grade foundation - which is most of Texas - a warm spot means a hot-water supply line is leaking beneath the concrete. Damp carpet with no source above it means the same thing.
4. Damp smell, or mildew in a cupboard
Persistent musty smell along a wall base or inside a vanity, with no obvious spill, means moisture is arriving from inside the structure.
5. Stains, bubbling paint, or sagging
Ceiling stains that grow, paint lifting off a wall, or a soft patch of drywall. On a ceiling this is urgent - saturated plasterboard eventually comes down.
6. Cracks, or doors that stop closing
A slow leak under a foundation changes the moisture in the soil, the soil moves, and the structure moves with it. New cracks in drywall or tile, and doors that suddenly bind, can be a plumbing symptom.
Confirm it with the meter test
- Turn off every tap, appliance and ice maker.
- Read the meter, or watch the low-flow indicator.
- Wait fifteen minutes, using no water.
- Read it again.
Any movement is a leak. If you want more certainty, do it overnight.
Then what
Shut the water off at the main if the leak is active and causing damage. Photograph everything before anything is repaired - insurers ask. Then get it located properly before anyone opens a wall or breaks slab: leak detection exists so the repair opens one square foot instead of ten.
Common questions
What is the fastest way to confirm a leak?
The meter test. Turn off everything that uses water, note the meter, wait fifteen minutes without using any, and read it again. Movement means water is escaping somewhere.
Can a leak raise a bill without any visible water?
Easily. A slab leak or an underground supply leak can run for months with the only symptom being the bill, because the water goes straight into the ground.