What causes a water main break?

Water main breaks occur for a number of reasons, but the most common reasons are age and temperature. All materials wear out over time, which can eventually result in a water main failure. Temperature is also a big factor. As the ground freezes, it contracts and puts pressure on the water mains. While unlikely, the water inside the pipe can also freeze resulting in an outward pressure on the water main. Hot temperatures and dry air can cause the ground to shift and settle, creating a shearing effect. Other factors that cause a water main break include:

  • Material - All materials wear out over time. Cast iron can become very brittle over time, increasing the likelihood it will crack as it expands and contracts with changing temperatures.
  • Erosion - If the soil around water main erodes due to a previous water issue, nearby construction, or other issues, the area around the main can become unstable.
  • Corrosion - Steel and cast iron pipes are not treated for corrosion, so they can wear through over time.
  • Accidents - Unfortunately, there are many human factors that can cause a water main break too. The most common is damage during construction and accidents often result in a water main break.

Show All Answers

1. What is a water main?
2. What causes a water main break?
3. What happens when a water main breaks?
4. Signs of a water main break?
5. What are signs of a water main break inside your home?
6. What are signs of a water main break outside your home?
7. What should I do after a water main break?
8. How long does it take to fix a water main break?