Leaks inside walls are some of the most damaging because they’re hidden. Water can soak framing, insulation and plasterboard for weeks before anything shows. Here’s how to narrow it down before you call in the trades.
How do you find a water leak inside a wall?
Look for stains, bubbling paint, swollen skirting and musty smells. Do a water meter test to check for a supply leak. Thermal imaging and a moisture meter can show where the wall is damp and how far it spreads. A licensed plumber then confirms and repairs the pipe, which may mean opening the wall.
Signs of a leak inside a wall
- Stain or tide mark spreading from a point
- Paint bubbling or wallpaper lifting
- Skirting boards swelling or coming away
- A soft or crumbly patch of plasterboard
- Musty smell in that room or cupboard
- Carpet edges damp along that wall
- Sound of running water with everything off
Step-by-step
- Do the meter test. Watercare advises 4+ hours (ideally overnight) without using water. A rising reading suggests a pressurised pipe leak. See our water meter test guide.
- Think about what’s in or behind the wall. Bathroom, laundry, kitchen, cylinder cupboard or an outside wall?
- Check when it gets worse. After showers? After rain? All the time?
- Map the damp. A thermal scan flags possible damp areas; a moisture meter confirms them.
- Call the right trade. Plumber for pipes and wet areas; roofer or building surveyor for outside water.
Clues to the source
| Pattern | Likely source | Who to call |
|---|---|---|
| Wet constantly, meter moving | Supply pipe | Plumber |
| Wet after showers only | Shower waste, seals or membrane | Plumber / shower specialist |
| Wet after heavy rain | Roof, window, flashing or cladding | Roofer / building surveyor |
| Wet on cold mornings, on outside walls | Possibly condensation | Improve ventilation; check with a meter |
Our shower leak case study shows how far shower water can travel.
Does the wall need opening?
Sometimes. A plumber may need access to repair a pipe. GIB’s guidance on water-damaged plasterboard says boards that were saturated or have wet insulation behind them may need removing so the cavity can dry. See can wet plasterboard be dried?.
Drying after the repair
When you hire our Drying Combo, our technician delivers the equipment and, where suitable, does a free on-site thermal imaging and moisture check. The dehumidifier and fans then help dry the wall and surrounding areas.
| Drying Combo | What you get |
|---|---|
| Equipment | Commercial 90 L dehumidifier + two drying fans |
| Testing | Free on-site thermal image assessment and moisture test, included where suitable |
| Delivery | Our technician delivers the equipment and does the testing on site; Auckland delivery and pick-up, subject to booking timing and site access |
| Price | $75 + GST per day (3-day minimum) or $400 + GST for 7 days |
See the full offer: free thermal imaging and moisture testing with the Drying Combo.
What thermal imaging and moisture testing can’t do
We’d rather be upfront:
- Thermal imaging indicates, it doesn’t prove. The camera reads surface temperature. A cool patch can be damp, but it can also be a draught, missing insulation, a cold-water pipe or shade from the morning sun. Our technician checks suspicious areas with a moisture meter on site before treating them as wet.
- Meters read accessible spots. A moisture meter gives a reading where it touches. It can’t see right through a sealed cavity, and we don’t cut open walls.
- It isn’t a plumbing repair. We can help show where water has spread. Finding and fixing a failed pipe, shower tray or fitting is a job for a licensed plumber.
- We’re drying specialists, not plumbers or inspectors. We aren’t a licensed plumber, a pre-purchase building inspector or an acoustic/tracer-gas leak detection specialist, and we’ll tell you when you need one.
- It isn’t a building report. This check supports your drying setup. It isn’t a pre-purchase inspection, a weathertightness report or a code compliance document. For roof, cladding or structural concerns, talk to a qualified building surveyor or inspector.
Frequently asked questions
How can I tell if a pipe is leaking inside my wall?
Look for stains, bubbling paint, swollen skirting and musty smells, and do a water meter test. If the meter moves with all water off, a pressurised pipe may be leaking.
Can thermal imaging find a leak in a wall?
It can show temperature patterns that may indicate damp in the wall, which helps narrow the area. It does not confirm the exact pipe; a plumber does that.
Will the plumber have to cut open my wall?
Sometimes, to access and repair the pipe. Saturated plasterboard or wet insulation may also need removing so the cavity can dry.
Can a wall dry out without being opened?
Minor wetting of surfaces can often be dried in place, but wet insulation or saturated board may need removal. Moisture readings help decide.
Does Dry Me Now repair leaks?
No. We are not plumbers. We provide drying equipment, and where suitable our technician does a free on-site thermal imaging and moisture check with Drying Combo hire.
Book the Drying Combo with a free moisture check
If you’ve had a leak, overflow or flood in Auckland, call Dry Me Now on 021 877 504 or use the enquiry form on our thermal imaging and moisture testing page. Tell us what happened and which rooms are affected, and we’ll confirm availability and delivery. Our technician delivers the machines and does the testing on site.