When it comes to water quality in sterile processing, it’s not just about what’s in the tank — it’s about what’s coming out of the faucet.
Since the release of ANSI/AAMI ST108:2023, there’s been a quiet but critical shift in how healthcare facilities are expected to monitor the water used for cleaning, disinfecting, and sterilizing medical devices. At the heart of this shift lies Table 6, which outlines the required frequency and scope of water quality monitoring at the point-of-use — the exact place where water touches instruments.
And yet, in many hospitals, Table 6 is still widely misunderstood. Based on what we hear from sterile processing and facilities leaders across the country, here are five common misconceptions — and the facts that challenge the status quo.
1. “We test at the RO system — that’s enough.”
Why it’s wrong:
ST108 draws a clear distinction between the water generation system and the point-of-use. Even with excellent upstream treatment, contamination can occur downstream in the storage tank, pipe loop, or fixtures — especially from biofilm, stagnant water, or corrosion.
Fact: ST108 Table 6 requires that Critical Water quality be confirmed at the point-of-use, not just at the output of your filtration system.
2. “We’re fine testing water quality once a year.”
Why it’s wrong:
Water quality isn’t static — it fluctuates with municipal supply changes, system maintenance, seasonal factors, and internal plumbing issues.
Fact: Table 6 requires quarterly testing at the point-of-use for microbial counts, conductivity, and TOC — and endotoxins, if applicable. Anything less is not compliant.
3. “If our RO system is working, the water must be clean.”
Why it’s wrong:
RO systems do a lot — but they’re not a silver bullet. They don’t eliminate endotoxins, and they can’t prevent microbial regrowth in downstream plumbing if proper sanitization and final filtration aren’t in place.
Fact: ST108 defines Critical Water by outcome — not by equipment. Final rinse water must meet specific quality criteria where it’s used, regardless of the treatment method.
4. “Endotoxin testing only applies to implantable devices.”
Why it’s wrong:
That’s outdated thinking based on limited applications. ST108 applies endotoxin testing to any use of Critical Water, particularly for final rinsing or steam generation.
Fact: If your sterilization process uses Critical Water and you’re not testing for endotoxins, you are out of compliance.
5. “Our equipment vendor tests our water, so we’re covered.”
Why it’s wrong:
Most OEMs check for basic parameters like hardness or chlorine at the inlet. They rarely test microbial load, TOC, or endotoxins at the point-of-use.
Fact: ST108 assigns responsibility to a multidisciplinary water quality team — not just the OEM. That includes SPD, Facilities, Infection Control, and Executive Leadership.
Why This Matters:
Non-compliance isn’t just a technicality. It’s a real risk. If your point-of-use water fails to meet Critical Water specifications, you may be putting your instruments — and patients — at risk of:
Biofilm and bacterial contamination
Residue and corrosion on devices
Sterilization failures and infection transmission
Failing a Joint Commission audit or CMS inspection
Want to Know If You’re Compliant with Table 6?
At VERDA Water Quality Systems, we specialize in full-spectrum ST108 compliance, including quarterly point-of-use monitoring, final filtration, and documentation that stands up to auditors.
- Request an evaluation to see how your current process compares
Because when it comes to water quality, what touches the instrument touches the patient — and that’s too important to overlook.