The state health department is warning the public to stay out of sewage-contaminated water that has collected in a drainage ditch in a residential area near Waianae Mall.

More than 10,000 gallons of raw sewage is estimated to have flowed from a broken line onto Farrington Highway before collecting in a drainage ditch that ends at the Lualualei Beach Park, resulting in a mix of sewage and storm water. The health department does not believe it has reached coastal waters.

Warning signs have been posted at Lualualei Beach Park and on Farrington Highway.

The department’s clean water branch began investigating a sewage spill from a private commercial property located along Farrington Highway and across from Ala Poko Street on Tuesday. The owners, who are required to remove contaminated water from the drainage ditch, have been notified of the damaged sewer pipe.

The branch will continue to monitor the area and investigate its cause.