Straight from the Tap

Why Do More Water Main Breaks Occur During Winter?

01/05/2018

Have you ever tried to dig a hole in the middle of winter only to find that the ground was frozen? When air temperatures drop below 32°F, the water in soil starts to freeze. The depth to which the ground freezes is called the frost line. The colder the winter and the longer the cold, the deeper the frost line will go causing more breaks and leaks on underground water infrastructure. 

The frozen ground adds pressure to anything beneath, including the underground distribution mains and service lines that pump water throughout the 80 communities in Cleveland Water’s service area.

Most Cleveland Water mains are at least 5 feet underground. In the summer, the weight of the soil above a pipe exerts a downward force of about 200 pounds for every foot of pipe. The pipes are constructed with materials designed to withstand this force.

But during harsh winters, the frost line goes deeper than usual, increasing the downward force on the pipe to 400 pounds per foot or more. The deeper the frost line, the more pressure on the water mains and the more likely the metal is to fracture under the pressure.

To a lesser extent, thermal contraction of pipe material plays a role. Materials expand or contract when subjected to changes in temperature. Most materials expand when they are heated, and contract when they are cooled. The underground pipes, like the soil above, cools and contracts in winter.

All piping systems expand and contract with changes in temperature. Cast iron, steel, and copper pipes change the least.

The age and brittleness of pipe materials is also a contributing factor. The mains in Cleveland Water’s Low, First High and Second High East service areas are the oldest, some 120+ years old. Most of these pipes are made of cast iron. The mains in other Second High and Third High areas are mostly 50 to 60 years old. Mains installed or repaired after 1970 are usually made from stronger, more flexible ductile iron. Many of the older pipes in the Cleveland Water system are made of cast iron, which is slightly more brittle than ductile iron. The cast iron pipes are also much older making them more susceptible to cracks and breaks. 

Cleveland Water is prepared for the increased number of main breaks during winter. We know that the average number of breaks in summer, about three per day, will double during an average winter or go high during extremely cold winters. We’ve added additional winter staffing, outfitted them with protective winter gear, and stockpiled parts and equipment required to repair breaks on mains, valves, connections and other parts of the distribution system, and have contractors available to assist with repairs.

Cleveland Water is also working to replace older mains that are more likely to break. Currently, we spend approximately $26 million a year replacing aging infrastructure buried underground. This means, over the next five years, we plan to spend nearly $130 million upgrading water mains which are often out of sight and out of mind to the general public.

At Cleveland Water, we are dedicated to keeping safe and healthy water flowing to our customers even when temperatures are freezing. If you spot a water main break, call our Emergency Line at 216-664-3060, 24 hours a day, 7 days a week.

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