About Water Treatment
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 (AAMI) and used by the Centers for Medicare and Medicaid Services for conditions for coverage.
The medical director should provide leadership by being engaged with the process, knowing the facility’s water source, and understanding water treatment system operation as well as the clinical significance of system failure.
Medical Director Responsibility Starts at the Water Source
Knowing the characteristics and potential vulnerabilities of your water source is the first step to ensuring your facility can and will deliver the safest and highest quality water for dialysis. Moreover, understanding your primary source of water will allow you and your biomed partners and support team to identify appropriate next steps should your primary source be compromised.
Discuss with your biomed:
- The natural source of your facility’s water and Annual Source Letter.
- Any processing of source water by municipal water utilities.
- Any secondary processing by other institutions, if applicable. (e.g. hospitals, building complex).
- The Water Contingency Plan to secure water for dialysis.
The Water Treatment Circuit
Monitoring
Monitoring the components of the water treatment system is a critical step to ensure safety within a dialysis facility. Safe operation of the water treatment system is demonstrated by observing, documenting and trending values throughout the water treatment system array. These daily readings at the facility may include, but are not limited to:
- Temperature
- Incoming Water Pressure
- Pressure differences across filters or media tanks
- Timer settings
- Total Chlorine Testing and Hardness Testing
- RO Performance Parameters (to include flow rates, quality and percent rejection)
Testing
The AAMI (Association for the Advancement of Medical Instrumentation) guidelines provide levels for microbiological culture and endotoxin testing, specifically, for acceptable, action level and unacceptable levels for water samples. These guidelines are crucial to ensure appropriate actions are taken, should system results necessitate additional interventions and testing.
Here's an explanation of the AAMI response levels for culture and endotoxin testing results:
| Test | Acceptable Level | Action Level | Unacceptable Level |
| Water Culture | < 50 CFU/mL | 50 - 99 CFU/mL | ≥100 CFU/mL |
| Water Endotoxin | < 0.13 EU/mL | 0.13 - 0.25 EU/mL | ≥ 0.25 EU/mL |
Dialysis quality water is also tested for chemical compounds on at least an annual basis (some states may require more frequent testing). Moreover, if there are seasonal variations in source water, RO performance declines, or membranes are replaced in the water treatment system, chemical analysis will additionally be performed.
Reviews
Your facility maintains various logs on: water treatment performance, machine disinfection, water culture results, endotoxin (LAL) test results, etc. that you should review for completeness, accuracy and, where applicable, appropriate follow up actions or interventions. Your facility’s biomed teammate should present results at each monthly Facility Health Meeting (FHM) for your review.
Clinical Significance
Dialysis patients are exposed to approximately 360 liters of dialysis quality water per treatment. Thus, it is important to eliminate water as a potential source of illnesses or symptoms in your facility’s patient population. Contamination of dialysis quality water can manifest as subtly as pruritus or as apparent as vomiting, acute abdominal pain or encephalopathy. Chronic exposure to contaminates in dialysis quality water can lead to chemical toxicity or infections. Conversely, optimizing water quality can improve patients’ response to erythropoietin and their overall quality of life.