As rainfall events become more frequent and intense, watershed management becomes paramount. Elevated bacteria levels in the nation’s surface waters are a public health issue–leading to sick pets, beach closures, and posing immediate health risks to anyone who recreates in or consumes the water. Until now, there have been limited, cost-effective ways to reduce bacteria levels in stormwater. Biochar in stormwater filter media could provide safer, cleaner recreational waters for humans, pets, and wildlife. During this presentation, Stantec will discuss the biochar- and iron-enhanced sand filters (BIESF) Large-scale Demonstration Projects. These BIESFs are the largest known stormwater treatment systems designed to remove bacteria from urban runoff with far-reaching implications for the industry. Key takeaways to be presented include biochar- and iron-enhanced sand filter design considerations and specifications, site constraints and challenges, preliminary performance results, and lessons learned along the way.