The Bondi Ocean Outfall Sewer is a heritage-listed sewerage infrastructure at Blair Street, North Bondi, Waverley Municipality, New South Wales, Australia. The sewer line commences at the intersection of Oxford Street and College Street in Darlinghurst and then travels in a more-or-less easterly direction for 6.1 kilometres (3.8 mi) passing through a number of suburbs until it reaches Blair Street in North Bondi. It was designed and built by the Public Works Department between 1880 and 1889. It is also known as BOOS (Bondi Ocean Outfall Sewer) and Main Northern Ocean Outfall Sewer. The property is owned by Sydney Water, an agency of the Government of New South Wales. It was added to the New South Wales State Heritage Register on 15 November 2002.