City officials say a break to a wastewater force main late Saturday caused about 614,400 gallons of raw sewage to spill onto undeveloped Navy land near the Waipio Soccer Complex in Waipahu.

None of the sewage reached either nearby West Loch nor the ocean, the city said. Crews from the Department of Environmental Services diverted the spill from the break in the 48-inch force main to a a 42-inch parallel force main to minimize the overflow, officials said.

The area affected by the spill was about the size of an Olympic-scale swimming pool, city spokesman Andrew Pereira said.

Environmental Services crews responded about 7:25 p.m. Saturday and secured the flow at about 2:45 a.m. Sunday, city officials said. The state Department of Health was notified and city crews spent much of Sunday cleaning, disinfecting and deodorizing the affected area.

The Navy land is marked with “no trespassing” signs at its entrances and the city is posting additional signs around the affected area and the entrances, officials said.

Residents between Halawa and West Loch are urged to conserve water to reduce the flow while the city addresses the force main break issue.

Environmental Services is still trying to determine the exact reason for the break, although it’s likely that it broke on its own, Pereira said.