Everett’s 33 miles of postwar water mains pose a challenge

EVERETT — The freezing weather that settled over the region last week called attention to one aspect of living in Everett: aging water pipes.

At least six water mains broke during the cold snap, including one Friday evening in the 2800 block of Grand Avenue. Most of those breaks occurred in cast iron pipes that were installed shortly after World War II.

The frequency of the breaks, which temporarily cut off water service to dozens of homes throughout the city, prompted Everett Mayor Ray Stephanson to weigh in during the Jan. 4 city council meeting.

He noted that the incidence of breakages was about average for the year 2016. The city recorded 24 water main breaks last year, compared with 25 in 2015. The latest breaks occurred in the first week of the new year aren’t included in those figures.

The common culprit in the recent breakages was substandard postwar construction, Stephanson said.

“They used a product we would not use today,” Stephanson said.

Everett has 33 miles of cast-iron pipe that date from the 1945-1955 period, out of a total of 415 miles of pipe in the city’s water system. Most of the postwar pipes are neighborhood mains located in the older north end of town.

“All the 33 miles or so are not breaking at the same rate. We have segments of those that perform worse than others,” said Mark Sadler, Everett’s public works maintenance superintendent. “Those are the ones we’ll target first.”

Cast iron is brittle compared with today’s ductile iron. When temperatures fluctuate above and below the freezing point, the pipes flex and can break.

That is one factor that may have led to the breakages last week, but determining the precise cause usually isn’t possible. Other factors at work include the age and type of pipe and the soil conditions at the time the pipe was installed.

“You can correlate but you can’t get a cause,” said Kathleen Baxter, a spokeswoman for Everett’s Department of Public Works.

But it’s not as straightforward as older pipes failing more quickly. There are many cities, including Everett, where older cast iron pipes continue to function well.

“We have pipes that date back to the early 1900s and they’re holding up just fine,” Baxter said.

Cast iron has been used for pipes since the 18th century, but many manufacturers compensated for poor quality control and inferior manufacturing by making pipes with thicker walls, said Yehuda Kleiner, a researcher at the National Research Council Canada.

Kleiner was the lead author of a 1999 study published in the Journal of the American Water Works Association that sought to forecast the likelihood of breakages in a large metropolitan area by using 20 years of water main repair data in one section of that city.

One finding that emerged from the data was a strong correlation between pipes that dated from the postwar period and more frequent failures.

“It has been observed that the pipes that were installed after 1945 until, I would say, the late 1950s, they exhibited a much higher failure rate at a much younger age,” Kleiner said.

Other correlations to pipe failure rate include the composition of the surrounding soil. Pipes installed in clay and peat showed faster rates of corrosion than those in sandy or rocky soils.

The postwar period proved problematic for infrastructure in many ways. The economic boom drove a rapid expansion of urban infrastructure, including water works.

“New companies with little experience started doing that, and they didn’t do it properly,” Kleiner said.

This was a common occurrence in many North American cities, he said.

Over the years, manufacturing processes and quality control improved, and in the 1970s, superior ductile iron pipes replaced cast iron.

Everett’s long-term capital plan calls for periodic replacement and refurbishing of its water mains. The city is expected to complete the replacement of 1,400 feet of pipeline along Broadway by the end of January, with paving work to follow as weather permits.

The Broadway main was first installed in 1956, which the city considers to be outside the more-likely-to-fail window.

Smaller neighborhood water mains are replaced as part of ongoing capital improvements.

“We spend about $2 million annually on water main replacement,” said Dave Davis, Everett’s public works director.

Davis said that the city is focusing on those pipe segments needing the most attention, to get them repaired more quickly. To do this, he plans to use more city crews for smaller jobs, bypassing the lengthier contracting process required for larger projects.

“We are going to refocus our efforts and approach this in a little more intense way,” Davis said.

Chris Winters: 425-374-4165; cwinters@heraldnet.com. Twitter: @Chris_At_Herald.