We are not able to say with certainty the exact cause of most water main breaks. We do know that there are several factors that contribute to water main breaks: age of pipe, type of pipe, soil and construction conditions when the pipe was installed, and temperature.
Pipe age and type: We find that post World War II cast iron pipes in our system made between 1945 and 1955 have a higher occurrence of failure. Cast iron pipes accounted for 70 percent of our repairs and breaks since 1992, but made up 80 to 85 percent of our repairs and breaks in the past five years. Other cities with similar pipe vintage have similar pipe failure rates.
Temperature: As temperatures move in and out of freezing, it’s not uncommon to see breaks occur.