Direct Potable Reuse (DPR) is the direct introduction of treated reclaimed water into the water supply system. After reclaimed water is treated at a Wastewater Treatment Facility, it would be treated a second time at an Advanced Water Treatment Facility. Advanced treatment options include: biological treatment, membrane filtration, membrane desalination, ozone, and advanced oxidation. The purified water is then held in a storage tank for final water quality testing before it is ready to be distributed directly to the Flagstaff community and the Lake Mary Water Treatment Plant.
Source: Modified from AWWA Potable Reuse 101
There are no pipe-to-pipe or direct-to-distribution DPR facilities operating the U.S. at this time