Why do water mains break?


Most of the water mains in Evansville are made of cast iron.


The average age of the Utility’s cast iron water mains is 90 years. Eventually, the condition of the water main and its surroundings can lead to cracks, joint failures or more serious breaks. Most often it happens when the age of cast iron pipes approach 100 years, but sometimes much younger pipes can break. Ideally, a main should be repaired or replaced before it completely fails.

  • These factors contribute to water main breaks:
  • The weight of the soil covering the main in the street, including surface weight of vehicles.
  • Vibrations due to nearby activities such as truck traffic.
  • Expanding wet soil from freezing.
  • Expansions and contractions of the pipe resulting from temperature changes. During winter, cold water flowing through the pipe causes the pipe material to contract, which stresses the joints. The smaller the pipe, the greater the stress on the pipe due to the proportional thickness of its walls.

Facts about water mains

  • 60% of Evansville’s water mains are cast iron, which was the water industry’s material of choice until the late 1950s. Ductile iron and PVC pipes are now the industry’s material of choice.
  • The average age of the city’s cast iron water mains is 90 years.
  • A cast iron water main is expected to function for 75 to 100 years.
  • The vast majority of water main breaks occur in the city's cast iron water main lines.
  • Evansville has approximately 1,000 miles of water mains.
  • Water mains range in size from 2 to 48 inches.
  • In 2013, EWSU repaired 315 broken mains.