This specification describes the required characteristics of
waters deemed suitable for use with the Standards under the
jurisdiction of ASTM.
The alphanumeric characters ascribed to water types and grades
are specified in the ASTM Format and Style Manual. These have been
assigned in order of historical precedence and should not be taken
as an indication of a progression in water purity.
Four types of waters have been specified, with three additional
grades that can be applied to the four types. The grade
specifications specifically address contaminants of microbiological
All applicable ASTM Standards are expected to reference one or
more of these reagent water types where reagent water is needed as
a component of an analytical measurement process. Where a different
water type or grade is needed for an ASTM Standard, it may be added
to this Specification through the ASTM Standard revision
Although these water types and associated grades have been
defined specifically for use with ASTM Standards, they may be
appropriate for other applications. It is the responsibility of the
users of this standard to ensure that the selected water types or
grades are suitable for their intended use. Historically, reagent
water Types I, II, III, and IV have been linked to specific
processes for their production. Starting with this revision, these
types of waters may be produced with alternate technologies as long
as the appropriate constituent specifications are met and that
water so produced has been shown to be appropriate for the
application where the use of such water is s pecified.
Therefore, the selection of an alternate technology in place of the
technology specified in Table 1 should be made taking into account
the potential impact of other contaminants such as microorganism
and pyrogens. Such contaminants were not necessarily considered by
the performance characteristics of the technology previously
Guidance for applications, the preparation, use and monitoring,
storage, handling, distribution, testing of these specified waters
and validation of the water purification system is provided in
Appendix X1 of this document.
The values stated in SI units are to be regarded as standard. No
other units of measurement are included in this standard.
This standard does not purport to address all of the safety
concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and
health practices and determine the applicability of regulatory
limitations prior to use.
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