Debris balls have washed up on Sydney’s beaches after heavy weekend rain. Malabar beach, near a sewage treatment plant, saw black and grey blobs scattered on the sand. Sydney Water put up a sign warning, "This area may be affected by sewage debris balls. Please do not touch any debris. We are cleaning the area and apologise for any inconvenience." The foul-smelling debris included lumps the size of half a house brick. A secret Sydney Water report said a huge fatberg, possibly as big as four Sydney buses, inside the Malabar deepwater ocean sewer is likely the cause of these debris balls. The report explained these blobs release during "sloughing events," caused by sudden changes in sewage pumping pressure after heavy rains or power outages. Sydney experienced a storm with over 100mm of rain in just a few hours. Debris also appeared on Foreshore beach near where Mill Stream flows into Botany Bay, a spot known for pollution as it’s near a major sewage overflow valve. Two Sydney Water contractors were cleaning the beach, removing wet wipes and chunks of grease. Sydney Water has a permit to discharge sewage into Mill Stream until 2027 and mainly uses primary treatment before releasing wastewater into the ocean through deepwater outfalls. Sydney Water CEO Darren Cleary said, "Deep ocean outfalls have been meeting environmental standards for nearly three decades." He called the debris balls an "unexpected event" and said water quality at Sydney beaches is usually very good. Sydney Water plans to improve sewage treatment at inland plants to recycle water, especially for industries like data centers. This will reduce sewage sent to ocean outfalls. The report warns fixing the fatberg would mean shutting down the Malabar outfall and diverting sewage, which could close beaches for months—a move considered unacceptable.