AAMI ST108 Compliance: Water Quality in Sterile Processing for Healthcare Facilities

Water quality has always played a critical role in sterile processing, but until recently, U.S. healthcare facilities had limited guidance on what “good water” really means for cleaning and sterilizing medical devices. That changed with the release of AAMI ST108: Water for the Processing of Medical Devices, a landmark standard from the Association for the Advancement of Medical Instrumentation (AAMI).

This new standard provides a comprehensive framework for ensuring water used in sterile processing is safe, consistent, and effective. For sterile processing departments (SPDs), facilities managers, and infection prevention teams, ST108 represents both a challenge and an opportunity: a challenge to raise practices to a new level, and an opportunity to better protect patients, staff, and valuable surgical instruments. HOH Water Technology (HOH) is uniquely positioned to help facilities navigate this transition, providing the expertise and treatment solutions needed to meet every requirement.

Why AAMI ST108 Matters for Your Healthcare Facility

Before AAMI ST108, water quality was addressed in AAMI TIR34, a guideline for water used for sterile processing, and only briefly in AAMI ST79, the widely used steam sterilization guideline. TIR34 covered many of the items in ST108 but was a guideline and not a standard, so held a lesser enforceability status. ST79 acknowledged water’s importance but did not define clear, measurable standards. This left many facilities uncertain about what parameters to monitor, how often to test, or what corrective actions to take when water quality drifted out of range.

ST108 changes that. It creates standardized expectations across the healthcare field, aligning U.S. practices with the science-driven approach already seen in international standards. The goal is simple: reduce patient risk, minimize damage to instruments, and eliminate variability in how hospitals manage their water.

HOH partners with SPDs and facilities teams to interpret these requirements, assess existing systems, and close the gaps; turning complex standards into practical, step-by-step solutions.

Key Elements of AAMI ST108 Compliance

1. Defined Water Categories

ST108 distinguishes between utility water (used for flushing, washing, and some rinsing steps) and critical water (used for final rinses and steam generation). Each category has its own specific quality requirements.

How HOH helps: We design and maintain treatment systems that reliably deliver both utility and critical water, tailored to your facility’s needs.

2. Measurable Parameters

The standard sets limits for microbial counts, endotoxins, hardness, pH, conductivity, and chemical contaminants. By putting numbers to these requirements, it gives facilities a clear benchmark for compliance.

How HOH helps: Our water testing and monitoring services ensure you not only meet but also maintain these parameters, with actionable reporting that your SPD can rely on.

3. Monitoring & Testing

ST108 outlines recommended testing frequencies and documentation practices.

How HOH helps: We provide routine testing programs, data trending, and defensible records – giving your team confidence in surveys, audits, and accreditation reviews.

4. Roles & Responsibilities

Because water quality spans multiple departments, ST108 emphasizes teamwork.

How HOH helps: We act as the bridge between sterile processing, facilities, and infection prevention, helping each group understand their role while keeping the focus on patient safety.

5. Continuous Improvement

The standard promotes a cycle of validation, verification, and corrective action.

How HOH helps: Our programs include ongoing reviews, system adjustments, and training to ensure continuous compliance, not just a one-time fix.

Benefits of Compliance

Adopting AAMI ST108 isn’t just about checking a regulatory box – it delivers real value:

• Improved patient safety by reducing microbial and endotoxin risk.
• Longer instrument life through reduced corrosion, staining, and scale buildup.
• More reliable sterilization thanks to water that meets steam generation standards.
• Defensible practices that demonstrate compliance with recognized national standards.

HOH works alongside your team to make these benefits a reality, ensuring your investment in compliance also enhances operational efficiency and protects equipment.

Moving Toward Implementation

For many healthcare facilities, achieving AAMI ST108 compliance will require investment in water treatment systems, staff training, and new monitoring routines. While this transition can feel overwhelming, HOH Water Technology is here to guide you through manageable steps, making the process smooth and efficient:

1. Form a multidisciplinary team (SPD, facilities, infection prevention, administration).
2. Conduct a risk assessment of current water systems and usage points.
3. Develop a ST108-specific water management plan or update a water management plan to include ST108 testing and control measures.
4. Partner with specialists like the HOH Pretreatment Team to design sustainable solutions for treatment, monitoring, and documentation.
5. Validate and verify results, then continuously review and refine processes.

Final Thoughts

AAMI ST108 represents a turning point for sterile processing in the United States. By defining clear water quality standards and expectations, it helps facilities protect patients, safeguard equipment, and manage risk to ensure consistent, high-quality outcomes. While implementation requires effort and collaboration, the long-term payoff – improved safety, compliance, and efficiency – makes ST108 a standard worth embracing.

HOH Water Technology offers the expertise, tools, and services needed to guide your healthcare facility through each stage of AAMI ST108 compliance. From water treatment systems to ongoing monitoring and staff support, we ensure your facility meets and sustains the highest water quality standards.