US · guidance
CMS SOM App. H, Tag V211
ANSI/AAMI RD52:2004 Requirements as Adopted by Reference 42 CFR 494.40(a)
5.3.3 Water distribution systems (continuous flow rates)
7 Strategies for bacterial control
7.1 General
5.3.3 Water distribution systems
Water distribution systems should be configured as a continuous loop and designed to
minimize bacterial proliferation and biofilm formation. A centrifugal pump made of inert
materials is necessary to distribute the purified water and aid in effective disinfection.
7 Strategies for bacterial control
7.1 General
To minimize biofilm formation, there should always be flow in a piping system. A
minimum velocity of 3 ft/sec in the distal portion of the loop of an indirect feed system and
a minimum velocity of 1.5 ft/s in the distal portion of a direct feed system are recommended
when the system is operating under conditions of peak demand.
Dead-end pipes and unused branches and taps that can trap fluid must be eliminated
because they act as reservoirs of bacteria and are capable of continuously inoculating the
entire volume of the system. These measures also minimize the possibility that pockets of
residual disinfectant could remain in the piping system after disinfection.
Interpretive Guidance § 494.40(a)
ANSI/AAMI RD52:2004
5.3.3 Water distribution systems
A multistage centrifugal pump is preferred for this purpose.
7 Strategies for bacterial control
7.1 General
Other measures can also help protect pipes from contamination.
Additional Guidance:
It is not the intent of this regulation to dictate the type of pump used for this purpose, other than
that the pump be made of inert material.
Page 74 of 420
It is not intended that surveyors would measure flow rates; responsible staff (i.e., the chief
technician) should be able to describe how the system is monitored to ensure at least minimum
flow, i.e. constant flow passing through the piping system, during operation.
The facility must identify and remove any potential dead-end pipes. For example, if the facility
has discontinued reprocessing dialyzers, any unused piping should be removed to prevent
stagnant water or trapping of disinfectant.
History
Rev.
Provenance
- Source
- cms.gov
- Retrieved
- 2026-07-22
- Edition
- som-2026-07-22
- Content hash
1cd049dc54fc88fcf6fec64c2a6d6d9d57c9a0e85d6dc5b1b932392a4026e7da
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