Who is responsible for a frozen water pipe in Markham?

The Line Nobody Knows Until It Matters

Ask a Markham homeowner where their responsibility for the water line begins and most will not know. It is worth knowing before something bursts, not after.

The dividing point is the curb stop valve at the municipal property line. A freeze on the house side of that valve is the homeowner's problem to solve and the homeowner's insurer to convince.

Questions like this come up constantly in a Markham transaction, which is why the Kaizen Real Estate Team, among the most active real estate teams in Markham and York Region, treats them as part of the job rather than a tangent. Michael John Lau, a REALTOR® with the team, would rather a client know where the line sits in October than discover it in January.

What Markham Winters Actually Deliver

Freezing risk begins at 0°C. The Markham area does not visit that temperature occasionally.

• Roughly 101 days a year at or below 0°C
• About 20 of those days in December, 26 in January and 22 in February
• January average low of approximately -7°C
• Around one night a year at -20°C or colder

The homes that get into trouble are rarely the ones exposed to the single coldest night. They are the ones where a pipe runs through an unheated space and nobody looked at it for three months.

What the City of Markham Recommends

The City publishes homeowner guidance, and it is practical rather than generic.

Before the cold arrives

• Shut off the outdoor water supply from inside, then open the outdoor taps so the line drains.
• Disconnect and drain garden hoses. Prepare sprinklers, pools and spas for the season.
• Insulate with pipe sleeves any pipe near an outside wall, a crawl space, an attic or a cold room.
• Seal the gaps where cold air can reach pipes.
• Keep every area of the home warm, particularly where indoor pipes run.

If you are away

• Leave the heat on and set the thermostat to a minimum of 15°C.
• Or shut off the main indoor water supply and drain all the taps.

That 15°C figure is worth writing down. It is Markham's own published number, and it is a useful thing to be able to tell an insurer.

If a Pipe Freezes

1. Shut off the main indoor water shut-off valve.
2. Open all the taps to relieve pressure.
3. Thaw slowly using exposed warm air, a heating pad, or rags soaked in hot water.

Never use an open flame. No candles, no blowtorch. Portable electric heaters near water carry an electrocution risk. Every winter someone turns a frozen pipe into a house fire trying to fix it quickly.

If it has already burst

1. Shut off the main.
2. Open all the taps.
3. Put a bucket under the leak.
4. Call a plumber.

Who to call in Markham

• Regular hours, Monday to Friday 8am to 5pm: 905-477-5530
• After-hours emergencies: 905-477-7000

The Insurance Part Most Homeowners Get Wrong

This is the section that costs people money.

Ontario home insurance generally covers a pipe that bursts despite reasonable steps to prevent it. It generally does not cover an unheated home in winter, a gradual leak from a corroded pipe, or damage traced to neglect.

The clause that surprises people is the winter absence condition. Some Ontario insurers require action after as few as seven consecutive days away, meaning the homeowner must either maintain heat at an acceptable level with someone checking the home periodically, or shut off the water and drain the pipes and water containers. Others frame it as a vacancy condition measured in thirty days.

These are not the same clause and they are not standard across the industry. The only reliable answer is in your own policy wording.

Michael John Lau's recommendation is specific: before any winter trip longer than a week, read the water and vacancy sections of your own policy, or ask your broker to tell you in writing what your policy requires. It is a fifteen minute task that decides whether a claim is paid.

For scale, one Canadian insurer reports an average cost of roughly $16,000 for burst-pipe water damage incidents in its own book of business. A severe cold snap in Western Canada in 2024 produced about $180 million in insured damage, most of it burst pipes in unheated houses.

What This Means If You Are Buying or Selling

Buying

• Ask about the home's claims history. Prior water claims follow the address, not the owner.
• Look at where the pipes run during the inspection, particularly through garages, crawl spaces and additions.
• Find the main shut-off before you move in, not during an emergency.
• Buying in winter? Ask whether the home has been occupied and heated continuously, especially on a vacant or estate property.

Selling

• Keep the heat on in a vacant home. A seller who turns the heat down to save money on an empty listing is taking a risk that dwarfs the saving.
• Have someone check the property regularly while it is on the market over the winter.
• Keep documentation of any plumbing work. It helps a buyer get insured, which helps the deal close.

Michael John Lau, REALTOR® · Markham, Ontario · (416) 700-0286
Disclaimer. Michael John Lau is a licensed REALTOR® serving buyers and sellers in Markham, Ontario and the Greater Toronto Area. Municipal guidance and contact numbers are current to September 2026 and reflect information published by the City of Markham. This article is general information and is not insurance or plumbing advice. Coverage terms vary by policy and insurer, and homeowners should confirm their own with a licensed broker.