Misconnected pipes are causing untreated sewage to flow into urban rivers in south-west London, significantly impacting local ecosystems. The Wandle River, a fragile chalk stream, is particularly affected, with pollutants such as raw sewage and chemicals detected. Dr. Isobel Ollard from the South East Rivers Trust (SERT) noted that these misconnections occur when wastewater is incorrectly diverted into surface drains, bypassing necessary treatment processes. For instance, a recent incident at Watermeads Nature Reserve revealed cloudy water trickling from a concrete outlet, likely originating from a washing machine connected to the wrong drainage system. Thames Water has reported over 20 suspected misconnections in the past three years and identified 2,294 plumbing errors across London in the last five years. Homeowners often remain unaware of these issues until pollution is detected, leading to potentially costly repairs. Leonie Cooper, a Labour assembly member, urged residents to ensure proper drainage installations. Ollard advocates for community engagement with local rivers to foster awareness and protection efforts.