Our lungs are 90% water, and our blood 80% source more than 80 percent water HowStuffWorks.com water consumption Our lungs are 90% water, and our blood 80% Our lungs are 90% water, and our blood 80% Our lungs are 90% water, and our blood 80% HowStuffWorks.com Our lungs are 90% water, and our blood 80% source 60% water and exhale approximately a cup of water