Managing hospital water quality beyond the treatment system

Hospitals can ensure water quality by looking beyond treatment equipment to the entire water system. Risks such as stagnation, dead legs and biofilm can develop within facility plumbing, making risk assessments, routine monitoring and multidisciplinary water management essential for protecting patient safety and supporting ANSI/AAMI ST108:2023: Water for the processing of medical devices¹ compliance.

Key takeaways

• Water quality risks can develop beyond the treatment system, including within hospital plumbing and distribution networks.
• ANSI/AAMI ST108 guides facilities to assess and manage water quality throughout the entire water system, not just at treatment.
• Dead legs, stagnation, and biofilm are common sources of water quality issues in healthcare environments.
• Cross-functional water management teams help identify risks and support compliance and patient safety.
• Routine monitoring and point-of-use testing help verify water quality where it matters most.

Every day hospitals reprocess thousands of surgical instruments, and every instrument depends on water that meets specific quality standards at the point of use. But the most persistent water quality risks aren’t just restricted to the treatment equipment. They live in the plumbing that carries water to the point of use — in dead legs where water stagnates and in distribution loops that lack proper flow.

The release of ANSI/AAMI ST108 in 2023 elevated the importance of water quality and exposed the hidden risks that can emerge beyond the treatment system itself. For healthcare leaders, the standard reflects a larger reality: ensuring water quality requires visibility and accountability across all water systems in a medical facility, not just the equipment that treats it.

Why do water quality risks persist beyond the water treatment system?

The water treatment system, which can consist of reverse osmosis, deionization, filtration and other treatment processes, is only the first step. What happens between treatment and the point of use determines whether the water that touches surgical instruments is safe. Distribution piping that includes dead legs and sections of pipe where water doesn’t flow continuously, create ideal conditions for biofilm; a layer of bacteria that adheres to pipe surfaces and protects microorganisms from disinfection. Once established, biofilm is extraordinarily difficult to remove.

Many hospital water systems predate current standards. Renovations and deferred maintenance accumulate over decades, creating pipe configurations that facilities must manage. Budget constraints limit what can be redesigned, and workforce shortages mean fewer people maintaining more complex systems. Meanwhile, patients who depend on properly reprocessed instruments are among the most vulnerable to contaminants which may be present due to improper water distribution.

Addressing water quality risks proactively can also help organizations avoid unnecessary water waste associated with repeated flushing, remediation efforts and equipment rework, supporting both operational and sustainability objectives.

As healthcare organizations work to meet ANSI/AAMI ST108 requirements, many are discovering that water quality challenges often originate in places that receive little attention until problems emerge. To better understand where these risks exist and how facilities can address them, we spoke with Matt Bero and Brian Battani about the most common issues they see in hospital water systems and the practical steps organizations can take to improve water quality management.

What are the most common design mistakes in hospital water systems for sterile processing?

We've found that water system design and equipment selection are often where problems originate. One example involves cart washers, which are typically the largest water consumers in a sterile processing department. When a cart washer is plumbed first in line and nothing restricts its demand, it draws as much water as it can, starving downstream equipment of the flow and pressure they need. The sequence of equipment on the distribution loop determines whether every point of use receives the water quality and quantity it requires.

How do dead legs create water quality risks?

In one facility, a plumbing contractor terminated a pipe run intended for a future cart washer with a pure water final rinse option. The facility never purchased that option, so the pipe just ended there, creating a massive dead leg. We identified that dead leg as the source of bacteria buildup. ANSI/AAMI ST108 addresses this with fully recirculating loops at the right flow velocities, because once you have dead legs or areas of low flow, you’re prone to biofilm formation.

Beyond system design, what ANSI/AAMI ST108 guidelines do facilities most often overlook?

One of the most overlooked parts of the standard is the need for a multidisciplinary team to conduct a risk assessment and determine where to test, how often to test and how to respond to adverse results. The team should include SPD leadership, infection prevention, facilities and surgical services.

The risk assessment piece is something a lot of facilities skip over. It establishes your baseline. You use that baseline data to understand where your primary risk areas are, and then you can develop a data-driven sampling plan.

Monitoring should extend beyond treatment-system performance. Facilities increasingly need visibility into water quality at the point of use, where changes in distribution conditions can affect outcomes. Tracking key indicators over time helps organizations identify trends early and validate that corrective actions are working.

What practical steps should facilities take first?

Start with a system-wide risk assessment. Understand where your distribution network may be vulnerable to stagnation, identify dead legs and low-flow areas, establish baseline water-quality data and develop a monitoring plan and corrective actions to be taken if testing results don’t meet the standard, before making major infrastructure investments.

How does Xylem help facilities address these pinch points?

We work with hospitals to assess water quality challenges and identify factors that may affect water quality throughout the facility. Our water solutions span treatment, monitoring and maintenance across the water cycle, so we can help facilities evaluate current conditions, implement corrective measures where appropriate and establish the monitoring programs needed to support ANSI/AAMI ST108 guidelines and verify water quality at the point of use.

As a result, facilities that address distribution system design flaws and implement data-driven monitoring can achieve consistent water quality at every point of use, reducing the risk of waterborne contamination and protecting patient safety.

What this shift means for healthcare water management

The shift from TIR34 to ANSI/AAMI ST108 signals a structural change. The bar for water purity in medical device processing has been raised. What was once the responsibility of facilities engineering alone is now shared across a multidisciplinary team. This collaborative model will become the standard for how hospitals manage water systems over the next decade.

For facility managers and sterile processing leaders, this means planning for water quality at the design stage of any renovation — not retrofitting compliance after problems emerge. It means investing in monitoring that provides continuous visibility into water quality and building partnerships with providers who understand the regulatory landscape and the operational realities of sterile processing.

Protecting patients starts with the whole system

As facilities modernize infrastructure, manage staffing challenges and adapt to evolving regulations, the ability to monitor and manage water quality from treatment to point of use will become an increasingly important part of operational resilience and patient safety.

At Xylem, we work alongside these teams. Our water solutions connect deep technical knowledge with the practical realities of sterile processing departments, from identifying hidden risks in distribution loops to implementing monitoring that gives teams confidence in their water quality. Together, we are solving water challenges that protect patients and build a more water-secure world.

As healthcare organizations adapt to ANSI/AAMI ST108 and evolving water quality standards, understanding risks throughout the entire system will become increasingly important. If your facility is evaluating its approach to water quality management, our health sciences team can help assess potential risks and opportunities for improvement.

^{1 American National Standards Institute https://blog.ansi.org/ansi/ansi-aami-st108-2023-water-quality-medical-devices/}