Water is a crucial resource for the earth and therefore for all living beings on earth such human. This article is focused on how to optimize water usage (saving) in industrial environment. This sector has a huge impact on water: usage, pollution, etc. The first step was to define and apply a water management and the second step to make research on each opportunity identified and to implement it. All those actions have been carried out in a pharmaceutical manufacturing site. Water saving have been done on different application: washing machine, heat pump on chiller system, osmosis inverses system on purified water and continuous measurement device of water quality. The site’s water consumption has been reduced by 40% in less than 6 years.