The medical directors of dialysis facilities have many operational clinic responsibilities, which on first glance, may seem outside the realm of excellence in patient care. However, a smoothly running clinic is integral to positive patient outcomes. Of the conditions for coverage outlined by the Centers for Medicare and Medicaid Services, one most critical to quality dialysis treatment is the provision of safe purified dialysis water, because there are many published instances where clinic failure in this regard has resulted in patient harm. As the clinical leader of the facility, the medical director is obliged to have knowledge of his/her facility's water treatment system to reliably ensure that the purified water used in dialysis will meet the standards for quality set by the Association for the Advancement of Medical Instrumentation and used by the Centers for Medicare and Medicaid Services for conditions for coverage. The methods used to both achieve and maintain these quality standards should be a part of quality assessment and performance improvement program meetings. The steps for water treatment, which include pretreatment, purification, and distribution, are largely the same, regardless of the system used. Each water treatment system component has a specific role in the process and requires individualized maintenance and monitoring. The medical director should provide leadership by being engaged with the process, knowing the facility's source water, and understanding water treatment system operation as well as the clinical significance of system failure. Successful provision of quality water will be achieved by those medical directors who learn, know, and embrace the requirements of dialysis water purification and system maintenance.