Water main breaks
Frequently asked questions (FAQ)
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- What is a water main break?
- How much notice will homeowners receive if their water needs to be turned off?
- Will customers notice anything different about their water after a water main break?
- How many kilometres of water mains are there?
- What causes water main breaks?
- Does cold weather cause more water main breaks?
- How many water main breaks happen in Winnipeg annually?
- What is cathodic protection and how does it prevent corrosion?
- How many crews work on breaks?
- How are they repaired?
- How do we determine which breaks to repair first on any given day?
- How much does it cost to repair an average water main break?
- How much do we spend to repair water mains annually?
- Who should you call to report a water main break?
What is a water main break?
A water main is an underground pipe that delivers water to the customer's service pipe. In suburban residential areas it usually runs under the boulevard. Along major streets and business districts it may run under the pavement. If a hole or crack develops in the pipe, the water will typically find its way to the surface. Because the water main is under pressure, water will continue to flow until the break is controlled.
How much notice will homeowners receive if their water needs to be turned off?
If water needs to be turned off for a water main break, homeowners will receive little or no notice. The water can flood streets and private property causing damage and safety hazards, and must be controlled as quickly as possible.
Will customers notice anything different about their water after a water main break?
After a water main break, customers may notice brown or cloudy water coming from their tap. If so, they should not use appliances or drink the water until it runs clear.
How many kilometres of water mains are there?
Winnipeg has 2466 kilometres of water mains. About 700 kilometres, or 30 percent, of mains are cast and ductile iron. Approximately 250 km of cast iron pipe still in service was installed prior to 1920, located in older sections of Winnipeg. The design life for cast iron pipe is 75 - 100 years.
What causes water main breaks?
Water main breaks usually result from external corrosion of the pipe. Winnipeg soil is highly conductive and corrodes the metallic pipe from the outside in. Changing soil conditions can then cause the weakened pipe to break.
Does cold weather cause more water main breaks?
Water main breaks are more likely to occur when frost penetrates deep into the ground, to a level of 5 - 6 feet, usually from late January until early April. While cold temperatures may send the frost deeper, the level of snow cover is also important. Snow will act as a "blanket" insulating the ground. In years when there is plenty of snow, the frost does not go as deep.
How many water main breaks happen in Winnipeg annually?
At our worst point, a little over 10 years ago, we were having 2200 water main breaks a year, or about 6 breaks a day. We have been able to reduce water main breaks by replacing corroded mains with new PVC pipe, and by reducing the rate of corrosion through cathodic protection. We now have only 600-700 breaks a year, or about 2 a day.
What is cathodic protection and how does it prevent corrosion?
Cathodic protection stops the corrosion of cast iron water mains by redirecting corrosion forces from the iron water main to a sacrificial zinc bar called an anode. We install anodes each time we repair a water main break. We also install them as part of an ongoing program to protect several blocks of pipes at a time. We spend $6.5 million on our annual water main renewal program and cathodic protection program.
How many crews work on breaks?
We have two shifts, covering 7 days a week, 11 hours per day. Each shift has four excavation crews repairing water main breaks, leaking or broken valves, and broken services. We also have two crews working in Emergency Services 7 days a week, 24 hours a day, so we can respond to water main breaks any time of the day or night.
How are they repaired?
First we control the water by closing valves. Then we contact other utilities to make sure we can dig without damaging other services or endangering staff or the public. We find the leak using an electronic leak detector, and then dig down to the pipe. Depending on the type of failure, we may apply a repair clamp or replace a length of pipe.
How do we determine which breaks to repair first on any given day?
We first repair breaks that could cause the most damage or hardship. Breaks which affect a large number of people (e.g., apartment blocks), or institutions (e.g., hospitals, personal care homes, schools), or traffic on major roads will be at the top of the list.
How much does it cost to repair an average water main break?
It costs about $4,000 to repair the average break.
How much do we spend to repair water mains annually?
In a typical year, we spend about $4 million to repair water mains. This amount will depend on the number of water main breaks.
Who should you call to report a water main break?
Contact 311.
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This page was last updated on January 16, 2009 |
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