As climate change intensifies, flooding events are becoming more frequent and severe, posing threats to communities, infrastructure, and economies. This Senix whitepaper highlights how ultrasonic sensors integrated with intelligent monitoring software form a core of scalable, real-time flood detection systems. It delves into system architecture, integration strategies, and case studies — such as deployment in the Iowa Flood Information System — to illustrate how these technologies enable more responsive and reliable water management across rivers, roadways, and coastal zones.