Signs You Have a Hidden Water Leak in Your Calgary Home

The most reliable signs of a hidden water leak are an unexplained increase in your water bill, the sound of running water when everything is turned off, damp or discoloured patches on walls or ceilings, a musty smell, and a water meter that moves when no water is being used. Any one of these is worth investigating. Several together strongly indicate a concealed leak.

A hidden leak does damage precisely because it is out of sight. Catching it early limits the cost and the repair.

If you have noticed any of these signs, our plumbing team in Calgary can locate the source and recommend the right repair. R N T Plumbing and Heating provides upfront pricing, a free plumbing inspection with every service, and a 5-year warranty on all parts and labour.

The Clearest Warning Signs

The five signs below show up in different ways, and any one of them on its own is worth a closer look.

An Unexplained Jump in Your Water Bill

If your water usage habits have not changed but your bill has risen noticeably, water is going somewhere. A sudden unexplained increase is one of the strongest indicators of a hidden leak, because the water is still being metered even though you are not using it.

The Sound of Running Water

If you hear water running, trickling, or hissing when every tap and appliance is off, that sound is coming from somewhere it should not be. Concealed pipe leaks often announce themselves this way before any visible damage appears.

Damp Patches, Stains, or Discolouration

Water stains on ceilings or walls, paint that is bubbling or peeling, or patches that feel damp to the touch all point to water escaping behind the surface. These stains often appear yellowish or brown and tend to spread or darken over time.

A Musty or Mouldy Smell

Persistent moisture creates the conditions for mould and mildew. If a particular area of your home has a musty smell that does not go away, especially in a basement, bathroom, or near plumbing, hidden moisture from a leak may be the cause.

A Water Meter That Keeps Moving

This is one of the most reliable tests you can do yourself. Turn off every water-using fixture and appliance in the home, then check your water meter. If it is still moving, water is flowing somewhere, which means you likely have a leak.

Simple Tests You Can Do Yourself

Before calling a plumber, there are a couple of DIY tests any Calgary homeowner can do to confirm a hidden leak and narrow down where it is. Neither requires special tools.

1. The Water Meter Test

Turn off all taps, appliances, and any devices that use water in the home. Locate your water meter and note the reading. Wait one to two hours without using any water, then check the meter again. If the reading has changed, water is escaping somewhere in your system.

2. The Inside-or-Outside Test

If the water meter test confirms a leak but you cannot spot where, this one narrows the location down significantly. Close the main water shutoff valve inside the home, then check the meter again after 30 minutes. If the meter has stopped, the leak is somewhere inside the house between that shutoff and your fixtures.

If the meter is still moving with the inside shutoff closed, the leak is upstream of it, which almost always means the underground water service line running from the street to the home. In Calgary, that section of pipe is the homeowner’s responsibility to repair, and the City of Calgary has a page explaining what the process looks like.

That is a very different repair and knowing which side of the shutoff the leak is on helps a plumber quote and diagnose faster.

These tests confirm a leak exists and can narrow down the general area but they will not pinpoint a concealed leak inside a wall, under a floor, or underground. That requires professional leak detection equipment.

Where Hidden Leaks Commonly Occur

Hidden leaks tend to develop in predictable places:

• Inside walls where supply pipes run
• Beneath floors and in crawl spaces
• Under concrete slabs, known as a slab leak
• At pipe joints and connections that have corroded or loosened over time
• Behind appliances such as dishwashers and washing machines
• Underground in the main water line between the meter and the home

In older Calgary homes, aging pipe joints and corroded galvanized pipes are common sources of concealed leaks.

Calgary’s housing stock adds a couple of specific patterns worth knowing. Homes built in the 60s and 70s often still have galvanized steel supply lines that pit and corrode internally over the decades. From the outside a pipe like that can look fine, while a slow leak develops behind the wall. Builds from the 80s and 90s frequently have Poly B piping, which is known for developing pinhole leaks at fittings and along the pipe itself, often hidden behind drywall for months before anyone notices. If your home is from either era, a hidden leak is more likely than in a newer PEX-plumbed build.

How Much Does a Hidden Leak Cost You?

A slow leak feels like a small problem until you do the math. A leak wasting just 1 litre a minute puts 1,440 litres a day down the drain and 43,000 litres a month. Even at Calgary’s water rates, a leak of that size can add $30 to over $100 a month to your water bill and larger leaks scale from there.

That is money going into a wall cavity, a crawl space, or the ground under your slab, not into anything useful. Add drywall repair, subfloor replacement, and mould remediation to the tab if the leak has been going for a while, and the total climbs fast.

Why You Should Not Wait

A hidden leak does not resolve on its own. Left unaddressed, even a small leak can lead to rotted framing, ruined drywall, damaged flooring, mould growth, and in the case of a slab leak, foundation issues. The cost of professional leak detection and repair is almost always far lower than the cost of repairing the accumulated water damage from a leak left to continue.

There is also an insurance angle worth understanding. Most Alberta home insurance policies cover sudden and accidental water damage, such as a burst pipe, but exclude damage from gradual or long-term leaks. If a hidden leak has been quietly running for months before anyone notices, the resulting claim may be denied or reduced. Acting on the first signs protects both your home and your coverage.

Suspect a Leak? Let Us Find It

Our team uses professional leak detection equipment to pinpoint the source without unnecessary tear-out, so you are not looking at a wall of drywall repair on top of the plumbing bill. Every service call includes a free plumbing inspection, so we can also flag anything else that might be developing.

Call (825) 883-9264 or book online.