US · guidance
CMS SOM App. H, Tag V210
ANSI/AAMI RD52:2004 Requirements as Adopted by Reference 42 CFR 494.40(a)
6.3 Water storage and distribution
6.3.2 Water storage (monitoring)
Routine monitoring of water storage tanks for bacteria and endotoxin levels is generally
accomplished indirectly by monitoring the water at the first outlet to the distribution loop
(see 6.3.3). If direct monitoring of a water storage tank is performed as part of a
troubleshooting process, bacteria and endotoxin levels shall be measured as specified in
ANSI/AAMI RD62:2001 (see 2.3). All bacteria and endotoxin results should be recorded on
a log sheet.
Interpretive Guidance § 494.40(a)
Additional Guidance:
Suggested water storage tank monitoring guidelines from ANSI/AAMI RD52, Table 4 include:
Measure bacterial growth and pyrogens, weekly, until a pattern of consistent compliance can be
demonstrated. Action levels for bacterial growth are 50 CFU/mL; for endotoxin 1 EU/mL.
Expect action to be taken for levels above 50 CFU/mL and above 1 EU/mL.
Page 73 of 420
A “pattern of consistent compliance” could be demonstrated by showing results within these
limits on weekly cultures for at least four weeks in a row. Laboratory generated reports are an
acceptable alternative to recording results on a log if the laboratory provides an aggregate
report allowing multiple monthly reports to be easily compared for trends.
History
Rev.
Provenance
- Source
- cms.gov
- Retrieved
- 2026-07-22
- Edition
- som-2026-07-22
- Content hash
504c40e740a4e2784a8c68c1e46db9e8211b943123198428cb54d846e9f3c4c4
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