PORTLAND, Ore. (KOIN) — Nothing can stop an old pipe from breaking when conditions come together. But the Portland Water Bureau has an ongoing effort to try and replace the most vulnerable pipes before they break.

The latest casualty of Portland’s unusually cold winter: a 16-inch cast iron water main, laid in the ground near SE 69th and Duke in 1930. It’s the 82nd water main break in Portland in a little over 3 weeks.

“To get 82 in less than one month is a phenomenal rate of breakage and it’s really correlated to the cold weather temperatures that we’ve had here in the last month or so,” said the bureau’s Ty Kovatch.

It’s not that pipes are freezing. It’s the cold water entering the city’s water supply network from Bull Run Reservoir.

Kovatch, who is the bureau’s Maintenance & Construction director, said as the water from Bull Run drops to 39 degrees pipes start breaking.

To try and keep ahead of the problem, the city monitors and tracks breakage rates and uses that information to proactively replace bigger sections of water main if they’ve had frequent isolated breaks on them in the past.

“In theory,” Kovatch said, “we’re eliminating problems that we might have with those that we believe are most likely to fail.”

There is more than 2200 miles of pipe in the Portland Water Bureau’s system. On average, between 5 and 12 miles of water main are replace a year.

Portland’s is a relatively young system compared with older cities in colder climates. But as the city learned the first 3 weeks of one of the coldest months in recent memory, cold weather causes water mains to break.