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Fixing water main breaks

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Two construction workers standing in a square hole dug in the road with mud up to their knees. They are both using saws to cut old pipe out of the hole.
The Portland Water Bureau’s Maintenance & Construction crews are ready to respond to emergencies, including water main breaks, 24-hours a day, and seven days a week. On average, crews respond to 200 main breaks a year.
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How main breaks happen

A main break occurs when the water main develops a crack or a hole that lets water out into the surrounding soil. On the surface, main breaks can look like leaks bubbling up out of the street, and, in extreme cases, the water can cause sink holes and flooding.

In Portland, cast iron water mains tend to break during the colder times of the year. Of the 2,250 miles of water pipe in the city’s network, approximately 1,300 miles are cast iron pipe. The majority of these cast iron pipes were installed before 1960 and remain in the water system.

Cold water can cause pipes to become more brittle. Adding cold air temperatures at or below freezing can cause the ground above a pipe to freeze and thaw, thereby increasing external stress on a pipe. Temperatures can be just one factor in causing a main break. The age of a pipe, soil conditions, pipe corrosion, and ground movement can also cause a main to weaken over time and break.

Fixing water main breaks

Every main break situation is different. A simple water main repair can be completed in six to eight hours, but large or complicated repairs may take several days to a week. Our response will vary based on the specific situation. However, in general, our crews fix a broken water main using the following steps: 

Step one: Respond to the site of the leak. Reduce the flow of the water by turning control valves. 

Illustration of two construction workers standing in a puddle on the street caused by a main break and working together to turn a handle to close a valve

Step two: Request marking of gas, electric, and other utility lines so we can dig safely. 

Illustration of a utility worker using paint to mark the road near the main break

Step three: Cut open the road and dig down to the pipe. 

Illustration of a backhoe next to a square hole in the road. In the hole is a broken pipe surrounded by dirt and water

Step four: Repair or replace the pipe.

Illustration of two construction workers guiding a new pipe into the hole in the road

Step five: Open a fire hydrant to pull clean water through the pipes, test water quality, then turn all the water back on. 

Illustration of a construction worker next to an orange fire hydrant that has water flowing out of it

Step six: Fill the hole and patch or put a plate on the street. Plan a permanent street repair. 

Illustration of a construction worker spreading fresh asphalt with a rake and a steam roller flattening the new asphalt

During and after a main break

During a main break, customers in the immediate vicinity may notice a reduction in water pressure or have their water temporarily shut off while repairs are being made. Customers may also experience discolored water. This color is from sediment that is always in our pipes and can get stirred up during a main break. Learn what to do during a discolored water event.

Reporting water main breaks and water quality issues

If you observe water running from streets or sidewalks, report the leak to the Water Bureau. Please call the Water Bureau’s 24-hour Emergency Line at 503-823-4874 for water system emergencies, including suspected main breaks.

If you experience ongoing water quality problems or lost water service with no notification, call the Water Quality Line at 503-823-7525, Monday through Friday, between 8:30 a.m. and 4:30 p.m. After hours, contact the 24-hour Emergency Line at 503-823-4874.

Prepare your own plumbing for winter weather 

Pipe breaks of all kinds are more common during cold weather, and your household pipes are no exception. You can take steps to protect your own plumbing from winter weather to reduce the risk of breaks. 

Prepare your plumbing for winter