What’s a water main break?

A water main is an underground pipe that delivers water to the customer's service pipe. Although main breaks can happen throughout the year, they’re most likely to occur during extreme weather conditions because air pressure that’s near or below freezing causes the ground above the pipe to freeze, increasing external stress on the pipe. 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 repaired.

What happens when a water main break occurs?

Main breaks can cause a loss of water pressure or even temporary loss of service as the main is shut down to isolate the emergency. Most interruptions to water service are fixed within six to eight hours. In some cases, such as water main breaks that occur in the middle of the night, water is usually restored by the following day.

While the potential for contamination of the drinking water is unlikely as a result of a water main break, often customers affected by a water main break will be placed under a precautionary boil advisory.

What’s a boil advisory and how will I be notified?

While the potential for contamination of the drinking water is unlikely, the Evansville Water & Sewer Utility may advise customers in the affected area to bring all cooking and drinking water to a complete boil for five (5) minutes before using. That should be done until customers are notified that it is no longer necessary.

Generally, customers who are under a boil advisory are notified with a door hanger on the front door of the property. If the area affected is large, and when it is not feasible to use a door hanger, the Utility will issue a media advisory. A different door hanger or media advisory is used when the boil advisory is lifted. Usually a boil advisory lasts about 48 hours.

What should you do after a water main break?

Repairs to water service can allow sediment and debris into pipes. Here are some tips for clearing debris from your water pipes after street repairs have been made:
  • Run your cold water faucets for several minutes to release air and remove debris from the system.
  • Use bathtub, laundry faucets and hose bibs when possible for flushing your system, as they generally have a larger capacity and do not have aerator screens to trap debris.
  • Clean faucet screens to remove debris that might clog the water fixture. 
How many miles of water mains are there in Evansville?

There are 1,000 miles of water mains buried beneath Evansville’s streets – more than enough pipe to connect Evansville to Denver. Imagine driving from here to Denver every year, checking the buried mains for leaks or problems that could lead to breaks.

Why do water mains break?

Most of the water mains in Evansville are made of cast iron. And 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.
Last updated: 2/12/2014 11:37:07 AM
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