What to Do When a Pipe Bursts

The entry in brief

Shut off the main water valve, keep away from electricity near the water, open a cold tap at the lowest point in the house to drain the lines, then call a plumber. After that, move valuables, start soaking up water and take photographs for your insurer. Everything else can wait a few minutes.

What is going on

Most bursts in Mississauga happen in winter. Water freezes in a pipe on an exterior wall, in an unheated garage or under a cantilevered floor, and the pressure behind the ice splits the pipe. Often nothing shows until the thaw, when water starts flowing through the split. Pipes can also fail from corrosion, a weak fitting or high pressure, and those failures can happen any day of the year. Either way, water keeps flowing until the supply is cut.

In order

1. Close the main shut-off. Most houses have it downstairs where the supply enters, near the street-side wall and the meter. Turn it clockwise. Our note on finding the main shut-off valve shows what it looks like.
2. Watch the electrics. Keep hands off outlets, lights and the panel if water is anywhere near. If you can reach the panel safely from a dry spot, turn off the affected circuits.
3. Drain the system. Run a cold tap downstairs and flush the toilets to drain the pressure off.
4. Turn down the water heater. Put a gas tank on pilot or vacation; trip the breaker on an electric one.
5. Contain the water. Use buckets, towels and a wet vacuum. Move rugs, electronics and boxes.
6. Record everything. Photograph the damage and the pipe. Keep receipts for anything you buy.
7. Call for help. Our emergency plumber page explains what we do on arrival.

Slips to avoid

• Searching for the leak before shutting the water off.
• Standing in water near live electrical outlets.
• Using an open flame or high heat to thaw a frozen pipe.
• Throwing away damaged items before your insurer has seen them.
• Turning the water back on to test before the repair is made.

When the ledger says phone

Right away, after the water is off. A split line deserves a real repair, not tape or a clamp left on all season, and a professional can check for other splits nearby. If you cannot find where the water is coming from, leak detection can trace it without opening every wall. Once the immediate repair is done, ask about the cause, especially if the pipe was in a cold spot; insulation, heat or rerouting may prevent a repeat. Our page on burst pipe repair covers the work in more detail, and frozen pipes prevention is worth reading before next winter.