The best papers from the three-day conference on Safe Drinking Water from Source to Tap June 2009 in Maastricht are published in this book covering the themes of challenges of the water sector and adaptive strategies, treatment, distribution, risk assessment and risk management, sensors and monitoring, small scale systems, simulation, alternative water supply & sources, consumer involvement, and future drinking water. Worldwide, the water supply sector is facing tremendous challenges. Every new emerging contaminants and pathogens and aging infrastructures that are vulnerable for deliberate contamination pose a threat to the quality of water supplies. Shortage of good quality and readily treatable resources is increasing due to global warming, urbanisation and pollution from agriculture and industry. Regulators and consumers are becoming more demanding. Techneau - the largest European project on drinking water - addresses these challenges by developing adaptive supply system options and new and improved treatment and monitoring technologies. Future system options to be studied are flexible, small scale and multi-source supplies, utilising non conventional resources like brackish ground water, treated wastewater and urban groundwater.