The Portland Bureau of Environmental Services plugged a leaking sewer pipe in Northeast Portland Saturday, but not before about 1,000 gallons of untreated sewer water seeped into an embankment near Northeast 21st Avenue and Interstate 84.

The 1,000 gallons is a very rough estimate, said Diane Dulken, bureau spokeswoman. “Our crews believe it’s been seeping for some time,” she said, and it’s impossible at this point to precisely determine the volume.

City crews started searching the area on the north side of I-84 after receiving a complaint of a foul odor.

The Bureau oversees 2,500 miles of sewer and stormwater pipe. Leaks are not uncommon, Dulken said. A third of the city’s sewer pipes are 80 years old or more.

The city makes public announcements any time sewage leaks into water or into a public area or if the volume exceeds 400 gallons, she said.

Unearthing and replacing aging portions of the system is an ongoing project. Currently the bureau is designing a project to make urgent repairs to 3,600 feet of public sewer pipes in downtown Portland. Originally installed between 1867 and 1917, these pipes are at a high risk of collapsing. New pipes should last 65 years.

Work crews installed a temporary fix on Saturday. Work will begin soon on a permanent solution, Dulken said.