A burst pipe is loud, obvious and comparatively cheap to fix, because you find it in minutes. The genuinely expensive losses are the quiet ones — a weeping fitting inside a wall, a slab leak under the kitchen, a shower pan that has been failing since 2019. By the time those announce themselves, remediation is already part of the scope.
1. The water bill moved and nothing else did
Compare this month against the same month last year, not last month. A twenty percent increase with no change in occupancy or irrigation is a leak until proven otherwise. To confirm it: close every fixture, note the meter reading, wait two hours without using water, and check it again. Any movement means water is going somewhere.
2. A musty smell you can locate but not see
Your nose detects microbial volatile organic compounds at concentrations well below what is visible. If one closet, one cabinet or one corner of a room consistently smells earthy, there is almost certainly growth inside that assembly.
3. Paint or wallpaper that bubbles in a line
Random bubbling is a paint adhesion issue. Bubbling in a straight vertical or horizontal line follows a pipe run or a framing member, and it means moisture is coming through the substrate.
4. A floor that has developed an opinion
Hardwood cupping at the board edges means moisture is coming from below. Tile that sounds hollow when tapped has lost its thinset bond to a wet substrate. Vinyl or laminate lifting at the seams is swelling from underneath. Flooring is the most honest moisture indicator in a house.
5. Nail pops and hairline cracks appearing in clusters
Drywall expands as it absorbs moisture and pushes fasteners out. A few nail pops across a house is normal settling. Six of them in one four-foot section of ceiling is a wet cavity.
6. One room that is always more humid
A $15 hygrometer will tell you more than most inspections. If one room consistently reads eight to ten points higher than the rest of the house, there is a moisture source in it. Condensation on the inside of windows in that room is the same signal.
7. Insulation that has changed shape
Attic insulation should be uniform and fluffy. Compressed, matted, discoloured or fallen patches indicate that water has been through it — and wet insulation holds moisture against the framing above your ceiling for weeks.
8. Symptoms that improve when you leave the house
Congestion, headaches, itchy eyes or a persistent cough that clears within a few hours of leaving home and returns within a day of coming back is a classic indoor air quality pattern. It is not proof of mold, but it is a strong reason to inspect.
9. A stain that keeps coming back through fresh paint
Painting over a water stain and watching it reappear means the source is still active. Stain-blocking primer covers a dry, resolved stain permanently. If it bleeds through, water is still arriving.
What to do if you recognise several of these
- 1Run the two-hour meter test to confirm or rule out an active supply leak
- 2Buy a hygrometer and log readings room by room over a week
- 3Check the attic in daylight for staining on sheathing and around penetrations
- 4Look under every sink and behind the water heater with a torch
- 5Book a professional moisture inspection if two or more signs are present
A thermal imaging and moisture inspection takes about ninety minutes and costs a few hundred dollars. Discovering a slow leak at month two instead of month eight is routinely the difference between a $900 repair and a $14,000 remediation.
Frequently asked
Months, routinely. We regularly find leaks that have been running for six months or more inside wall cavities, under slabs or in crawl spaces. The damage grows the entire time, which is why the early indicators above matter more than they look.