The Livings Building Challenge is a building certification program it is also known as a tool or philosophy. The reason it is called a tool is because it measures how sustainable a building is.
The challenge is broken down into 7 categories called petals. The petals are place, water, energy, health, happiness, materials, equity and beauty. There is much more detain on these categories because then they are broken down into 20 other categories but these are called imperatives. Every building has to follow the requirements and you can find the requirements and full description of the challenge in the Living Building Challenge 3.0
While the LEED Water Use Reduction is to further increase water efficiency within buildings to reduce the burden on municipal water supply and water waste systems.
Helps designers develop strategies to further assist the water usage of a house or building. The overall goal is to use less water than what the normal base line water usage calculated. The GradingSystem is is by percentage. 30% reduction is 2 points, 35% reduction is 3 points. and 40 % reduction is 4 points.