Direct Potable Reuse

Advanced Purification of Class A+ Reclaimed Water

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.

Direct Potable Reuse Cycle

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
  • Arizona is expected to adopt regulations allowing DPR in 2018. Check out the current Draft Rule for Reclaimed Water Quality Standards on ADEQ.
  • DPR could replace groundwater as our base water supply, greatly reducing groundwater pumping 
  • Operations involve 24/7 staffing of highly skilled persons
  • Are reclaimed water and DPR are mutually exclusive or if we should continue providing reclaimed water for appropriate uses?

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