Rice purchases 80 percent of its water from the City of Houston (see rates) which draws surface water resources from Lakes Livingston, Conroe, and Houston, as well as deep underground wells tapping the Evangeline an Chicot aquifers. The remaining 20 percent of Rice's water is supplied by an on-campus well.
Air conditioning systems provide a constant source of clean, cold water that is well-suited for reuse. In the fall of 2008, Rice began capturing condensate water from the air conditioning systems of the Biosciences Research Collaborative to use as make-up water in the cooling towers of the South Plant. This is a free source of water that Rice would otherwise have to buy from the City of Houston. During the summer of 2011, Rice completed a project to capture condensate water from many of the science buildings to bring back to the Central Plant's cooling towers. Combined, these systems are estimated to save at least 12 million gallons of water per year, which is equivalent to about 5 to 6 percent of Rice's annual water consumption in a typical year.
Dual-Flush toilets have two options, full flush, and partial flush. Full flushes use 1.6 gallons of water and partial flushes, which vary between buildings due to toilet model, use either .8 or 1.1 gallons of water. There are more than 400 dual-flush toilets located in several buildings on campus. It is estimated that 788,715 gallons of water per year will be saved because of the dual-flush toilets. That is enough water to fill an Olympic-sized swimming pool once every 10 months.
During the spring of 2011, the Rice Housing and Dining department partnered with the student eco-rep for Hanszen College to test a new showerhead that reduces water consumption by 40 percent with an economic payback of just a few months. The student and his roommates reported that the low-flow showerhead provided a better shower than the showerhead it replaced. With student support, during the summer of 2011, both Hanszen and Lovett Colleges were retrofitted with these new showerheads and retrofits in other campus housing facilities are scheduled for the fall of 2011.
In 2019, the Office of Sustainability began installing water sub-meters around campus on campus buildings, irrigation systems, plant processes, and reuse water sources to monitor consumption and detect leaks. By identifying and fixing leaks detected by these meters, Rice has been able to save almost double the initial cost of the meters themselves. Sub-metering like this also provides more reliable data regarding the campus' water usage. So far, 81 of these sub-meters have been installed and more are slated to be added in the near future.