Recent heavy rainfall led to high river levels and significant erosion, causing the riverside bank of the overflow pond at the Eltham Wastewater Treatment Plant to collapse on 5 July 2025. As a result, approximately 70% of the pond’s partially treated wastewater was discharged into a tributary of the Mangawhero Stream.
As a precaution, please avoid swimming, gathering kai (fish, shellfish, or plants), or coming into contact with the water at affected locations downstream in the Mangawhero and Waingongoro Rivers, including Castle Street Bridge in Eltham and Ōhawe Beach, until further notice.
If you have any further questions, please direct them to contact@stdc.govt.nz