Another "green" initiative to the building was reincorporating the roughly 100 year old 60,000 gallon cistern that is connected to a series of pipes that collects rainwater from the roofs of other buildings on campus. Today, the cistern collects between 4 million and 6 million gallons of water annually. The water is used to heat and cool Parmer Hall, irrigate the soccer field and provide water for other landscaping projects. In years past, all the water coming into the cistern was pumped into River Forest's sewer system. Today, it gets turned around and reused. The university is even using the cistern to hold groundwater that has to be pumped out of the basement at a rate of 20 to 30 gallons a minute to prevent flooding. It is estimated that the campus is diverting 3.6 million gallons of water from the municipality's sewer system.