Wastewater is any water that has been used and is commonly referred to as sewage.

Council owns and runs 18 sewerage schemes throughout Southland at Balfour, Browns, Edendale-Wyndham, Gorge Road, Lumsden, Manapouri, Monowai, Nightcaps, Ohai, Otautau, Riversdale, Riverton, Stewart Island, Te Anau, Tokanui, Tuatapere, Wallacetown and Winton.