If you’re not measuring water quality at the generation system — on a schedule, across multiple parameters, and with documented results — you’re not compliant with ANSI/AAMI ST108:2023
Why Table 5 Matters
In the world of medical device reprocessing, the quality of water is no longer just a facilities concern — it’s a frontline patient safety issue.
ANSI/AAMI ST108:2023 was created to establish measurable, enforceable water quality standards in healthcare facilities. While much attention is (rightly) given to water at the point-of-use (Table 6), Table 5 quietly sets the foundation — defining how and how often hospitals must monitor water at the generation system, where treatment begins.
Here’s what Table 5 says — and why it reveals serious blind spots in many hospitals’ current practices.
What Table 5 Requires (and Most Facilities Overlook)
Table 5 outlines the required monitoring frequency for Critical Water generated by your water treatment system. This includes reverse osmosis (RO), deionization (DI), filtration, and softening systems used to produce water for sterilization, final rinses, and high-level disinfection.
Key required monitoring parameters include:
Critical Water:
- Daily monitoring
Conductivity
- Monthly monitoring of microbial and physical parameters
pH
Alkalinity
Total hardness
Bacterial count (CFU/mL)
Endotoxins (EU/mL)
Utility Water:
- Quarterly monitoring of these parameters
Conductivity
pH
Alkalinity
Total hardness
Many hospitals only test conductivity or rely on basic service reports from OEM vendors — which leaves major compliance gaps.
Common Compliance Gaps We See
1. “We test when there’s a problem.”
Reactive testing is no longer acceptable. ST108 requires a proactive monitoring program, not just troubleshooting after a device is stained or a sterilizer fails.
2. “Our vendor tests the system — we’re good.”
Most vendors do not test for endotoxins or TOC, and some only test source water, not final product water. Under ST108, the facility — not the vendor — is responsible for compliance.
3. “We monitor conductivity — isn’t that enough?”
Conductivity is only one of several quality indicators. ST108 emphasizes chemical, microbial, and physical purity. Failing to test for bacteria, endotoxins, or total hardness can lead to audit failures and patient risk.
4. “We don’t keep test records — just service reports.”
ST108 requires documentation, trending, and response. If you can’t show data over time or a plan for corrective action, you’re not compliant.
What Compliance Looks Like Under Table 5
A compliant facility under ST108 Table 5 will:
- Test at least quarterly for microbial, chemical, and physical parameters
- Include endotoxin and TOC testing in Critical Water evaluations
- Maintain a documented monitoring schedule
- Assign responsibility to a multidisciplinary team
- Track, trend, and respond to any alert or action levels
- Keep records available for Joint Commission, CMS, or state audits
The Takeaway: Monitoring = Accountability
Table 5 isn’t just about water — it’s about the infrastructure of accountability behind sterile processing. Without reliable water generation monitoring, everything downstream — including point-of-use — is on shaky ground.
And here’s the reality: most water quality vendors are still quoting from pre-ST108 playbooks that leave out endotoxin testing, documentation, or point-of-use oversight. VERDA was built for exactly this standard — and we design, monitor, and service systems that stand up to regulatory scrutiny.
Want to Know If Your Current Monitoring Plan Meets ST108?
We’ve created a free Table 5 Monitoring Compliance Checklist you can download and use to evaluate your current water quality practices.
Because when it comes to water quality, guessing isn’t just risky — it’s now officially non-compliant.