Duke University obtains all of its potable water from the City of Durham, which receives its raw water supply from the Lake Michie Reservoir and the Little River Reservoir. The Flat River feeds into Lake Michie and the Little River feeds into the Little River Reservoir. If necessary, Durham has a number of alternatives for accessing additional water in order to supplement these sources including the Teer Quarry and allocations from neighboring towns. The City is studying expansion options for both the Lake Michie and Little River reservoirs, but there are many hurdles to expansion.
The University and the Hospital are the largest consumers of water in the City of Durham, and in fiscal year 2010 Duke used 449 million gallons of water. The largest water users at Duke are the Central Chilled Water Plants, the Hospital, and the School of Medicine.
In addition to potable water usage, Duke uses some non-potable water for irrigation and other purposes. This water comes from underground wells, rainwater cisterns, and retention ponds on the University grounds. It is estimated that 10-15 percent of water used for irrigation is non-potable.