7 Signs of a Water Service Line Leak and What to Do in Toronto

If left for too long, a hidden underground leak can cause serious damage to your home. If you’ve been receiving higher water bills than expected or experiencing low water pressure, pooling in your yard, or dampness near your home’s foundation, you’ll need to resolve these issues quickly. Although they don’t always mean you have a broken service line, you should understand the warning signs and know where your home’s main water shut-off valve is. We’ll explain the warning signs of a possible water line leak, what you can safely check, where to find your main shut-off valve, and who to call for help as a Toronto homeowner.

Municipal Water Main Versus Private Water Service Line

When people discuss a water main break, they may be referring to any part of the water supply system. In Toronto, it is important to make this distinction because responsibility for repairing the issue depends on the leak’s location.

The municipal water main is located in the street. The section of the pipeline owned by the City usually runs from the street water main to the property line. In contrast, the private water service line extends from the property line into the home.

If the leak occurs on the private portion, the homeowner is typically responsible for the repairs. However, if the issue is on the qualifying City infrastructure, the City will take care of the repair.

Basic water service line diagram:

If you are unsure where the leak is, do not guess. A plumber, qualified contractor, or the City may need to confirm the location.

7 Warning Signs of a Possible Water Service Line Leak

1. Sudden Unexplained Increase in Water Use

A sudden increase in water usage could indicate a leak, but first check for indoor issues such as running toilets, dripping faucets, or leaking appliances. Compare the spike to your usual usage before assuming there’s an underground leak.

2. Low Water Pressure Throughout the Home

A weak faucet may indicate a local issue, but low pressure throughout the home can suggest more serious problems, such as a supply issue, valve problem, leak in the main line, or a restriction.

3. Wet, Soft, or Unusually Green Areas in the Yard

Wet patches, soft soil, or unusually green grass may indicate underground leakage, but could also result from irrigation, poor drainage, grading issues, or heavy rainfall. If these areas are near the water service line, consider water leak detection.

4. Water Appearing Near the Foundation

Water near the foundation should be checked quickly. It may come from rain, downspouts, grading issues, plumbing leaks, or a damaged water line. Early inspections can help prevent larger problems.

5. The Water Meter Moves When Fixtures Are Off

Your water meter can help show whether water is moving when it should not be. Turn off all fixtures and appliances, then observe the meter. If it continues to move, there may be a leak, including a hidden indoor leak.

6. Discoloured or Cloudy Water After Pressure Changes

Discoloured or cloudy water after a pressure change isn’t always the result of a broken pipe. Nearby construction, pressure fluctuations, or an issue with the public water supply may cause it. If you suspect a problem from the City’s side, contact Toronto 311.

7. Hissing or Running-Water Sounds

A hissing or running water sound may indicate a leak. Listen near the water meter, basement entry, foundation wall, and where the water line enters the home. If the sound persists even with the fixtures off, have it checked.

How to Perform a Basic Water-Meter Leak Check

A water-meter check can confirm water movement, but it will not identify the exact leak location.

Turn off faucets, appliances, irrigation, and anything else using water. Make sure toilets have stopped refilling. Record the meter reading or take a photo. Avoid using water for a short period, then check the meter again.

If the reading changes, the source could be an indoor plumbing leak, toilet leak, appliance issue, underground water leak, or main water line leak. If the source is not obvious, contact a plumber.

Where Is the Main Water Shut-Off Valve?

The main water shut-off valve is commonly found where the drinking-water pipe enters the home. In many Toronto homes, it is located on the foundation wall near the water meter. You may find it in the basement, utility area, mechanical room, or near the front wall.

For a round handle valve, turn it clockwise until it stops. For a lever-style valve, turn the handle so it sits across the pipe. Do not force a valve that is seized, corroded, or difficult to move. If the private shut-off valve does not work, Toronto homeowners can contact the City for a property-line shutoff.

Who Should You Call?

If the leak is inside the home, contact a plumber. If the leak appears to be on the private water service line, contact a plumber or qualified contractor. If you suspect a City-side water main break, contact Toronto 311.

If water is near electrical equipment, avoid the area and seek emergency help. If there is an uncontrolled private plumbing leak and it is safe to do so, shut off the water and contact an emergency plumber.

What to Do While Waiting for Help

Shut off the private water supply if it is safe. Move valuables away from water and avoid electrical hazards. Take photos of visible damage.

Do not dig to search for the pipe, and do not use chemical products. Keep the area clear so the plumber or technician can inspect it safely.

Main Water Shut-Off Valve and Water Main Leak FAQs