A hidden water leak doesn’t stay hidden forever. It shows up in your water bill first, then in a damp patch on the ceiling, a soft spot in the floor, or eventually a mould problem that costs far more to remediate than the leak itself would have cost to fix. The damage is rarely dramatic until it’s expensive.
Professional Plumbing and Drain Services locates and repairs hidden water leaks across Toronto, North York, Scarborough, Etobicoke, Mississauga, and the wider GTA. We use non-invasive detection tools that find the source without tearing open walls or floors unnecessarily — and we give you a flat-rate repair quote before any work begins..
Warning Signs of a Hidden Water Leak
Hidden leaks can go undetected for months in finished basements and inside walls. Watch for:
- Unexplained spike in your City of Toronto water bill — Toronto charges by consumption, so a leak running continuously adds up fast. A single dripping pipe losing just 10 litres per hour adds over 7,000 litres to your monthly bill.
- Damp or discoloured patches on walls, ceilings, or around the base of fixtures
- Soft, warped, or buckled flooring — especially around bathrooms and kitchens
- Musty smell in a room or inside cabinets under sinks — often the first sign of a slow leak behind the wall
- Sound of running water when everything is shut off
- Low water pressure at fixtures throughout the house, which can point to a supply line leak underground or within the walls
- Hot spots on the floor in homes with in-floor radiant heating — can indicate a slab leak in the heating line
Any one of these warrants a professional inspection. Multiple symptoms together mean call today.
Why GTA Homes Are Particularly Vulnerable
Toronto’s housing stock creates specific leak risks that newer-build homeowners don’t face:
Aging galvanized and copper supply lines. Homes built before 1970 in areas like the older Toronto core, East York, and parts of North York often have galvanized steel supply lines. These corrode from the inside out, narrowing over decades before eventually pinholing or failing — sometimes inside finished walls where the leak runs silently for months.
Early copper with lead solder. Mid-century copper pipe is generally durable, but the lead-tin solder used at joints before 1990 corrodes at connection points. Pinhole leaks at fittings are common in homes from this era.
Seasonal freeze-thaw stress. GTA winters push pipes near exterior walls through repeated freeze-thaw cycles. Micro-cracks develop over years and worsen every winter until the pipe fails — usually during a January cold snap when plumber demand is at its peak.
How We Find Your Leak — No Unnecessary Demolition
The old approach to leak detection meant cutting into drywall and hoping. We don’t work that way.
Step 1 — Pressure testing. We isolate sections of the supply and drain system and test pressure to confirm where the loss is occurring and narrow the location.
Step 2 — Acoustic listening equipment. For pressurized supply lines, acoustic leak detectors amplify the sound of water escaping through a pipe wall, allowing us to pinpoint leaks beneath concrete slabs, behind drywalled walls, or underground — without opening anything.
Step 3 — Thermal imaging (where applicable). Active water leaks create temperature differentials that thermal cameras read through finished surfaces. Particularly useful for slab leaks and in-floor radiant heating systems.
Step 4 — Video camera inspection. For drain line leaks and suspected sewer line cracks, a waterproof camera gives us a live view of the pipe interior.
Step 5 — Quote, then repair. Once we’ve located the leak, you get a flat-rate repair quote in writing before we open anything. If the repair requires cutting drywall or concrete, we tell you exactly where, why, and what it will look like when finished.
Leak Detection and Your Home Insurance
Many GTA homeowners don’t realize that their insurer may require a licensed plumber’s written report confirming the source and nature of an active leak before approving a water damage claim. If you’re dealing with water damage and planning to claim, call us early — we can provide the documented inspection report your adjuster needs.
How Much Does Leak Detection Cost in Toronto?
A professional leak detection inspection in the GTA depending on the scope of the search and tools required. Repair costs vary with the location and severity — a faucet valve seat is a minor fix; a supply line under a concrete slab is a more involved job. Either way, you get a flat-rate quote before any repair work begins.
The cost of detection is almost always a fraction of the water damage repair, mould remediation, or inflated water bills that a missed leak produces.
Leak Detection FAQ
Check your water meter with all taps and appliances off. If the leak indicator dial is moving, you have an active leak. Other signs include unexplained increases in your water bill, damp patches on walls or ceilings, musty odours, and the sound of running water when nothing is on.
Yes. Professional Plumbing uses acoustic listening equipment, pressure testing, and thermal imaging to locate leaks through finished surfaces before recommending any demolition. In most cases, we can pinpoint the leak to within a small area, which minimizes the access cut required.
Most leak detection inspections in the GTA run between $150 and $300. Repair costs depend on the location and severity of the leak. You receive a flat-rate quote in writing before any repair work starts — call +1 (437) 247-7856 for a same-day estimate.
Pinhole leaks in copper pipe are most commonly caused by internal corrosion from aggressive water chemistry, electrolytic reactions between copper and other metals in the system, or degraded lead-tin solder at fittings. They’re particularly common in GTA homes built between 1950 and 1990. A single pinhole can release hundreds of litres per week into a wall cavity before any visible sign appears.
Most home insurance policies require documentation from a licensed plumber confirming the source and nature of a water leak before a claim is processed. Professional Plumbing can provide a written inspection report on the same visit as the detection service.