Warning signs are now posted at Kalihi Stream after sewage spilled from a backed-up sewer on Amelia Street in Kalihi, the state's Department of Health Clean Water Branch said.

About 250 gallons overflowed due to a clog caused by grease at 1508 Amelia St., officials said. About 150 gallons flowed into Kalihi Stream. Water samples will be collected. The public is advised to stay out of Kalihi Stream until water tests indicate bacteria levels have returned to normal, officials said.