PORTLAND, Ore. (KOIN) — Officials in Portland are warning people against recreating in the Willamette River until about Wednesday after about 11,000 gallons of sewage spilled into the water overnight.

The Bureau of Environmental Services says the discharge happened overnight near the Morrison Bridge after a malfunction at a nearby pump station.

Anyone recreating in the Willamette River is asked to avoid contact with river water between the Morrison and Fremont bridges for about 48 hours.

Officials say the discharge happened at a pump station on Southeast Alder Street around 2 a.m. Monday and lasted about six minutes, with a possible other discharge happening around 9 a.m. on Monday.

Although the amount of sewage discharge is low compared to how many millions of gallons of wastewater are treated each day — 11,000 gallons compared to 70 million — the bureau says it is issuing the advisory because of the potential for higher bacteria levels in the Willamette River.

Officials say the investigation into how the discharges happened is ongoing.