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.
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 2,100 miles of water pipe in the city’s network, approximately 1,350 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. The Water Bureau’s response will vary based on the specific situation. However, this is a general sequence of events that happen to fix a main break.
- The Water Bureau is notified of a possible water main break.
- Urgent response personnel respond to the site to determine whether the leak is indeed a water main break.
- If determined to be a water main break, valves are partially closed to reduce the flow of the water through the main, limiting any potential damage the water could cause.
- The area is blocked off for safety and traffic is rerouted.
- Other utilities, such as PGE and NW Natural Gas, are contacted to mark utilities lines that will help to ensure that excavating the break area in the street will not damage other services or endanger bureau staff or the public.
- The Water Bureau repair crew brings in heavy equipment, including a backhoe, to excavate the site and expose the break.
- The main break is assessed and crews determine how extensive the repairs will be.
- Repair may require the crew to temporarily shut off water service to customers who are notified before their water service is turned off at the water meter.
- The repair crew then cuts out and replaces the section of the damaged pipe.
- The excavation is backfilled with rock.
- The new main is flushed.
- Water service is restored to the affected customers.
- The repair crew ensures the backfilled excavation site is safe for traffic before removing the detour.
- The Portland Bureau of Transportation completes the restoration of the street at a later date.
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.
Affected Customers – During & After 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. The discoloration does not pose a health risk. However, customers should avoid using hot water or running the washing machine or dishwasher until flushing is complete.
If you have experienced discoloration in your water, run the water at one tap for five (5) minutes to see if it clears. If it does not clear, wait an hour and try again. When the water runs clear, flush any taps where discolored water was present. Take a look at our online Discolored Water fact sheet for additional information.
Reporting Water Main Breaks, Water Quality Issues
Anyone observing water running from streets or sidewalks is encouraged to 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 customers experience ongoing water quality problems or lost water service with no notification, call the Water 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.