Water for the processing of medical devices

The national standard for water used in the processing of medical devices. It establishes minimum water-quality requirements for cleaning, rinsing, disinfection, sterilization, and steam generation to help protect patients, medical devices, and processing equipment.

The standard addresses water selection, treatment, distribution, storage, monitoring, maintenance, qualification, and continuous quality improvement. It also outlines responsibilities for a facility-wide water management program and provides guidance for identifying and troubleshooting water-quality problems.

A central concept is selecting the appropriate water quality for each stage of processing. ST108 identifies Utility Water, Critical Water, and Steam as the primary categories. Utility Water is generally used for washing and intermediate rinsing, while Critical Water is used for applications such as final rinsing of critical or semi-critical devices and as feedwater for process steam.

The standard emphasizes that improper water quality can cause corrosion, scaling, biofilm formation, increased microbial or endotoxin levels, reduced cleaning effectiveness, and equipment degradation. These problems can ultimately contribute to patient infection, toxicity, or pyrogenic reactions.

ST108 also calls for a multidisciplinary water management approach involving facilities engineering, sterile/medical device processing, infection prevention, clinical engineering, procedural staff, water-treatment specialists, and organizational leadership. Responsibilities include testing water, managing treatment systems, monitoring processing areas, assessing risks, and taking corrective action when specifications are not met.

Ongoing monitoring and qualification are major components of the standard. Facilities are expected to confirm that water systems consistently deliver the required quality, monitor for changes over time, and respond when contaminants such as microorganisms, metals, or endotoxins exceed acceptable limits.

In short: ST108 provides a framework for ensuring that the water used throughout medical device processing is appropriate, controlled, monitored, and consistently maintained, reducing risks to patients while supporting effective cleaning, disinfection, sterilization, and equipment performance.