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Office of Ground Water and Drinking Water

February 6, 2013

MEMORANDUM

SUBJECT: Basis for Expedited Approval of Methods from the 22nd Edition of Standard Methods for 

the Examination of Water and Wastewater

FROM: Jennifer Best, Microbiologist, Technical Support Center

TO: The Record

 This memo documents the review that was conducted on methods published in the 22nd edition of 

Standard Methods for the Examination of Water and Wastewater. It provides the background 

information on why EPA is approving these methods using the expedited method approval process. 

Each method is discussed individually below:

(1) Standard Method 9215 B. The version published in the 20th edition of Standard Methods for the 

Examination of Water and Wastewater was used as the basis for comparison, because it is currently 

cited in the drinking water regulations at 40 CFR 141.74(a)(1) for the determination of heterotrophic 

bacteria. The version of this method published in the 22nd edition of Standard Methods for the 

Examination of Water and Wastewater is similar to the approved version with some minor editorial 

revisions that do not impact the effectiveness of the method. Therefore, the 22nd edition version of this 

method is as equally effective as the promulgated version of the method.

(2) Standard Methods 9221 A, B. The versions published in the 20th edition of Standard Methods for 

the Examination of Water and Wastewater were used as the basis for comparison, because they are 

cited in the drinking water regulations at 40 CFR 141.21(f)(3), 40 CFR 141.74(a)(1) while more 

specifically, SM 9221B.1,B.2 is cited in 40 CFR 141.852(a)(5) for the determination of total coliform 

bacteria. The versions of these methods published in the 22nd edition of Standard Methods for the 

Examination of Water and Wastewater are similar to the approved versions with some minor editorial 

revisions that do not impact the effectiveness of the methods. Therefore, the 22nd edition versions of 

these methods are as equally effective as the promulgated versions of the methods.

(3) Standard Method 9221C. The version published in the 20th edition of Standard Methods for the 

Examination of Water and Wastewater was used as the basis for comparison, because it is cited in the 

drinking water regulations at 40 CFR 141.74(a)(1)for the estimation of total and fecal coliform bacteria

density. The version published in the 22nd edition of Standard Methods for the Examination of Water 

and Wastewater has editorial revisions along with modified Most Probable Number (MPN) tables which 

were developed with improved statistical approaches. The changes to the version of the method 

published in the 22nd edition of Standard Methods for the Examination of Water and Wastewater do not 

impact the effectiveness of the method. Therefore, the 22nd edition version of this method is as equally 

effective as the promulgated version of the method.

(4) Standard Method 9221 E. The version published in the 20th edition of Standard Methods for the 

Examination of Water and Wastewater was used as the basis for comparison, because it is cited in the 

drinking water regulations at 40 CFR 141.21(f)(5) and 40 CFR 141.74(a)(1) for the determination of fecal

coliform bacteria . The version of this method published in the 22nd edition of Standard Methods for the 
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Examination of Water and Wastewater is similar to the approved version with some minor editorial 

revisions that do not impact the effectiveness of the method. Therefore, the 22nd edition version of this 

method is as equally effective as the promulgated version of the method.

(5) Standard Method 9221 F. The version published in the 20th edition of Standard Methods for the 

Examination of Water and Wastewater was used as the basis for comparison because it is cited in the 

drinking water regulations at 40 CFR 141.402(c)(2) and more specifically 9221 F.1 is cited at 40 CFR 

141.852(a)(5) for the determination of Escherichia coli. The version of this method published in the 22nd

edition of Standard Methods for the Examination of Water and Wastewater is similar to the approved 

version with some minor editorial revisions that do not impact the effectiveness of the method. 

Therefore, the 22nd edition version of this method is as equally effective as the promulgated version of 

the method.

(6) Standard Method 9222 D. The version published in the 20th edition of Standard Methods for the 

Examination of Water and Wastewater was used as the basis for comparison, because it is cited in the 

drinking water regulations at 40 CFR 141.74(a)(1) for the determination of fecal coliform bacteria. The 

version of this method published in the 22nd edition of Standard Methods for the Examination of Water 

and Wastewater is similar to the approved version with some minor editorial revisions that do not 

impact the effectiveness of the method. Therefore, the 22nd edition version of this method is as equally 

effective as the promulgated version of the method.

(7) Standard Method 9223. The version published in the 20th edition of Standard Methods for the 

Examination of Water and Wastewater was used as the basis for comparison, because it is cited in the 

drinking water regulations at 40 CFR 141.21(f)(3), 40 CFR 141.852(a)(5), 40 CFR 141.74(a)(1) for the 

determination of total coliform bacteria, and at 40 CFR 141.402(c)(2) and at 40 CFR 141.852(a)(5) for the 

determination of Escherichia coli. The version of this method published in the 22nd edition of Standard 

Methods for the Examination of Water and Wastewater is similar to the approved version with some 

minor editorial revisions that do not impact the effectiveness of the method. Therefore, the 22nd

edition version of this method is as equally effective as the promulgated version of the method.