United States 

Environmental Protection 

Agency 

Office of Chemical Safety 

and Pollution Prevention 

(7510P) 

EPA 712-C-07-074 

May 11, 2011 

Product Performance 

Test Guidelines 

 

 OCSPP 810.2600: 

Disinfectants for Use in 

Water—Efficacy Data 

Recommendations 
2

NOTICE 

 This guideline is one of a series of test guidelines established by the Office 

of Chemical Safety and Pollution Prevention (OCSPP) (formerly the Office of 

Prevention, Pesticides and Toxic Substances (OPPTS) prior to April 22, 2010), 

United States Environmental Protection Agency for use in testing pesticides and 

chemical substances to develop data for submission to the Agency under the 

Toxic Substances Control Act (TSCA) (15 U.S.C. 2601, et seq.), the Federal 

Insecticide, Fungicide, and Rodenticide Act (FIFRA) (7 U.S.C. 136, et seq.), and 

section 408 of the Federal Food, Drug, and Cosmetic (FFDCA) (21 U.S.C. 346a), 

referred to hereinafter as the harmonized test guidelines. 

 The harmonized test guidelines serve as a compendium of accepted 

scientific methodologies and protocols that are intended to provide data to inform 

regulatory decisions under TSCA, FIFRA, and/or FFDCA. This document 

provides guidance for conducting appropriate tests, and is also used by EPA, the 

public, and the companies that are subject to data submission requirements 

under TSCA, FIFRA and/or the FFDCA. At places in this guidance, the Agency 

uses the word “should.” In this guidance, use of “should” with regard to an action 

means that the action is recommended rather than mandatory. As a guidance 

document, these guidelines are not binding on either EPA or any outside parties, 

and the EPA may depart from the guidelines where circumstances warrant and 

without prior notice. The methods contained in this guideline are strongly 

recommended for generating the data that are the subject of the guideline, but 

EPA recognizes that departures may be appropriate in specific situations. You 

may propose alternatives to the methods recommended in these guidelines, with 

your supporting rationale. The Agency will assess such proposals on a case-bycase basis. 

 For additional information about OCSPP harmonized test guidelines and 

to access the guidelines electronically, please go to http://www.epa.gov/ocspp 

and select “Test Methods & Guidelines” on the left side navigation menu. You 

may also access the guidelines in http://www.regulations.gov grouped by Series 

under Docket ID #s: EPA-HQ-OPPT-2009-0150 through EPA-HQ-OPPT-2009-

0159, and EPA-HQ-OPPT-2009-0576. 

DRAFT DOCUMENT DISCLAIMER: This draft document is distributed solely for 

the purpose of external review. It has not been formally disseminated by the 

EPA and should not be construed to represent any Agency determination or 

policy. The information correction process under the Agency’s Information 

Quality Guidelines does not apply until this document is formally disseminated by 

the EPA in its final form. This draft document should only be cited or quoted in 

the context of providing comments.
3 

OCSPP 810.2600: Disinfectants for treating water – efficacy data 

recommendations. 

 (a) Scope.— 

 (1) Applicability. This guideline describes test methods that EPA believes will 

generally satisfy testing requirements of the Federal Insecticide, Fungicide, and 

Rodenticide Act (FIFRA) (7U.S.C. 136, et seq.) and the Federal Food, Drug, and 

Cosmetic Act (FFDCA) (21 U.S.C. 346a). It addresses testing to demonstrate the 

effectiveness of antimicrobial pesticides bearing label claims for the disinfection of 

water. 

(2) Background. The source materials used in developing this OCSPP test 

guideline are OPP guidelines 91-8 Products for treating water systems and 91-30 

Acceptable methods (Pesticide Assessment Guidelines, Subdivision G, Product 

Performance, EPA report 540/9-82-026, October 1982). 

 (b) Purpose. This guideline addresses efficacy testing for antimicrobial 

pesticides intended to be used in water systems, namely drinking water and swimming 

pools, as disinfectants. 

 (c) General considerations. –(1) This guideline recommends methods for use in 

tests to be conducted to address the data requirements for pesticide registration. Good 

Laboratory Practice Standards (GLP) as defined in 40 CFR Part 160 apply to studies of 

disinfectants for water systems. According to 40 CFR §160.17: “EPA may refuse to 

consider reliable for purposes of supporting an application for a research or marketing 

permit any data from a study which was not conducted in accordance with this part.” 40 

CFR §160.12(b) requires with any submitted research data “[a] statement describing in 

detail all differences between the practices used in the study and those required by this 

part.” Note: The Association of Official Analytical Chemists (AOAC) recommended 

tests are designed to be conducted as written. For deviations (e.g., cultures grown with 

shaking instead of static, dilution of culture prior to drying on carriers) proposed to be 

used in the conduct of these tests, obtain written approval from the Agency and 

document such deviations in the study reports submitted to the Agency. The Agency 

may consult with the AOAC prior to accepting modifications to their standardized 

methods. Refer to OCSPP Test Guideline 810.2000 for general testing 

recommendations prior to initiating tests. 

 (d) Drinking water for humans—(1) Public water systems. Applicants should 

contact EPA’s Antimicrobials Division prior to conducting studies to support label claims 

for disinfection of public water systems. 

 (2) Emergency water supplies. This section addresses efficacy testing for 

additives such as solutions, powders, or tablets intended for emergency disinfection of 

small quantities of drinking water of questionable potability (e.g., water obtained from 
4 

lakes, streams, etc), by the general public, in the absence of bacteriological monitoring 

facilities. 

(i) Test procedure. The Agency recommends the use of The Guide Standard 

and Protocol for Testing Microbiological Water Purifiers (Ref. 1). Three samples of 

product, representing three different batches, one of which should be at least 60 days 

old, should be tested in triplicate. The test organisms should be Raoultella terrigena – 

American Type Culture Collection (ATCC) 33257 (R. terrigena) (formerly designated as 

Klebsiella terrigena), Polio 1 (LSa) (ATCC VR-59), Rotavirus (Wa) (ATCC VR-2018), 

Cryptosporidium parvum (C. parvum) and Giardia intestinalis (G. intestinalis) (formerly 

Giardia lamblia). Giardia muris may be tested in place of Giardia lamblia.

(ii) Evaluation of success—(A) Bacteria. A 6-log10 (99.9999 percent) 

reduction of an influent challenge of 1 x107 organisms per 100 mL of the bacterial 

challenge organism R. terrigena should be demonstrated by the testing. 

(B) Viruses. A 4-log10 (99.99 percent) reduction of a mixed influent challenge of 

1 x 107

 organisms per liter of each of the following viruses: Poliovirus (LSa) and 

Rotavirus (Wa) should be demonstrated by the testing. Virus types should be mixed in 

roughly equal 1 x 107

/L concentrations and a joint 4-log10 reduction should be 

demonstrated. 

 (C) Cysts (Protozoan). A 3-log10 (99.9 percent) reduction of an influent 

challenge of 1 x 106 organisms per liter of C. parvum and G. intestinalis (and G. muris if 

tested) should be demonstrated by the testing. 

 

 (3) Water purifier units. This section addresses efficacy testing for products 

bearing label claims for microbiological water purification (removal of pathogenic 

microorganisms). This section does not apply to products only used to treat water in 

order to achieve specific chemical removal from water or other non-microbiological 

claims. National Sanitation Foundation (NSF) Standards 42 (Aesthetic Effects) and 53 

(Health Effects) provide partial guidance for chemical removal and other claims testing. 

 (i) Test procedure. The Agency recommends the use of The Guide Standard 

and Protocol for Testing Microbiological Water Purifiers (Ref. 1). This is a general guide 

and in some cases may present only the minimum features and framework for the 

testing of microbiological water purifiers. Users of the Guide Standard and Protocol 

should include pre-testing of their units in a testing rig, including the sampling 

techniques to be used. In some cases, it may be appropriate to alter and/or add to the 

guide in order to meet specific operational problems, to use an alternative organism or 

laboratory procedure, or to respond to innovative treatment units. However, these 

alterations and/or additions should not decrease the level of testing or alter the intent of 

the protocol and should be submitted to the Antimicrobials Division for approval prior to 

initiation of testing. 
5 

 (ii) Evaluation of microbiological water purifier success—(A) Bacteria. A 6-

log10 (99.9999 percent) reduction of an influent challenge of 1 x 107

 organisms per 100 

mL of the bacterial challenge organism Raoultella terrigena (ATCC) 33257) should be 

demonstrated by the testing. 

(B) Viruses. A 4-log10 (99.99 percent) reduction of a mixed influent challenge of 

1 x 107

 organisms per liter of each of the following viruses: Poliovirus (LSa) (ATCC-VR59) and Rotavirus (Wa) (ATCC-VR-2018) should be demonstrated by the testing. Virus 

types should be mixed in roughly equal 1 x 107/L concentrations and a joint 4-log10

reduction should be demonstrated. 

(C) Cysts (Protozoan). A 3-log10 (99.9 percent) reduction of an influent 

challenge of 1 x 106 organisms per liter of Cryptosporidium parvum and Giardia 

intestinalis (formerly Giardia lamblia) and Giardia muris (if tested) or a 3-log10 reduction 

of an influent challenge of 1 x 107 particles or spheres of 4 to 6 um diameter (as an 

option for units or components based on occlusion filtration, where disinfection or other 

active processes are not involved) should be demonstrated by the testing. 

(e) Swimming pool, spa, and hot tub water. This section addresses efficacy 

testing for disinfectants bearing label claims for use in swimming pools, spas, and hot 

tubs. Numerous factors influence the concentrations necessary for disinfection of 

swimming pool water in practical applications: the number of swimmers/bathers in the 

pool, frequency of use, frequency with which water is changed; general weather 

conditions; and types and degree of organic contamination of the water by the 

swimmers/bathers themselves (e.g., suntan lotion and oils) and by various debris. 

Therefore, a two-phased study, consisting of a laboratory test and confirmatory field 

test, is recommended. 

(1) Test procedure - Laboratory test. The Agency recommends the use of the 

AOAC International Disinfectants (Water) for Swimming Pools (Ref. 2). The test 

organisms should be Escherichia coli (E.coli) (ATCC 11229) and Enterococcus faecium

(E. faecium) (ATCC 6569) (formerly designated as Streptococcus faecalis). 

(i) Evaluation of success. The lowest concentration of the test substance 

providing results equivalent to those of the sodium hypochlorite reference standard is 

the lowest concentration of the product that can be considered effective. 

(2) Test procedure - Field test. The Agency recommends efficacy data to be 

derived from in-use tests under an experimental use permit (EUP) in at least two 

swimming pools, using the following components. 

(i) Bacteriologic monitoring. Bacteriologic monitoring of swimming pool water 

following treatment with disinfectant product during the field test should be conducted in 

the following manner: Water samples for bacteriologic monitoring should be taken on 

opposite sides of the pool in the shallow area and as remote as possible from the inlets, 

preferably at the midpoint between the inlets. A minimum of 144 samples should be 
6 

collected during the test period. Samples should be taken just below the surface of the 

water and preferably at such times when the number of persons using the pool during 

the preceding hour has been at least equal to 50 percent of the maximum bather load of 

the pool and the number of persons in the pool water at the time the samples are 

collected is at least 25 percent of the maximum bather load (as defined in Suggested 

Ordinance and Regulations Covering Public Swimming Pools, APHA Joint Committee 

on Swimming Pools and Bathing Places) of the pool (Ref. 3). Pertinent chemical 

characteristics (e.g., pH, nitrogenous substances, metals, and water hardness) of the 

pool water at the sampling site should be determined at the time of sampling. (Ref. 4) 

(ii) Field test. Field tests should be conducted for an entire swimming season 

(4 to 12 months). Reports should include (but are not limited to) the following 

information. 

(A) The daily swimmer/bather load. 

(B) The design of the pool, the recirculation and filter system, and water 

capacity. 

(C) The amount and identification of all chemicals added daily to the swimming 

pool water (including the time, site, and method). 

(D) The range of chemical characteristics of the swimming pool water such as: 

pH, nitrogenous substances, metals, and hardness. 

(E) The physical characteristics of the swimming pool water, including 

temperature and clarity, determined at least daily. 

(F) Meteorological data, including air temperature, rainfall, and number of hours 

of sunlight (determined daily) for outdoor pools. 

(G) Bacteriologic monitoring, conducted daily, in accordance with the suggested 

Ordinance and Regulations Covering Public Swimming Pools of the American Public 

Health Association. (Ref. 3) 

(H) The concentration of the antimicrobial agent in the swimming pool monitored 

daily at the same time intervals that the bacteriological assay samples are obtained. 

(I) The method that the product user will employ for monitoring the level 

(concentration in ppm) of antimicrobial agent contained in the pool water. 

(iii) Evaluation of field testing success. The product, when used as 

recommended in swimming pool water, should demonstrate that not more than 15 

percent of the samples collected fail to meet the following bacterial indices (Ref. 3): 

(A) The standard plate count at 35°C not to exceed 200 colonies/1.0 mL. 
7 

(B) The most probable number of coliform bacteria to be less than 2.2 

organisms/100.0 mL. When the membrane filter test is used, no more than 1.0 coliform 

organism/50 mL. 

 (C) The most probable number of enterococcal organisms to be less than 2.2 

organisms/100 mL. When the membrane filter test is used, no more than 1.0 

enterococcal organism/50 mL. 

 (f) Data collection and reporting—(1) General. To assist in the proper review and 

evaluation of product performance, complete descriptions of the test employed and the 

results obtained should be submitted to the Agency. All test reports should include, at 

the least, the following information: 

 (i) Study title; 

 (ii) Product Identity;

 (iii) Guideline number/Data Requirement; 

 (iv) Identification of the testing laboratory or organization;

 (v) Location where the test was performed;

 (vi) Name(s) of the person(s) responsible for the test;

 (vii) Statement of Confidentiality Claims;

 (viii) Statement of 40 CFR Part 160 Good Laboratory Practice compliance and 

Quality Assurance Statement;

 (ix) Purpose of the study;

 (x) Date and time of the start and end of the test;

 (xi) Test employed and any modifications (e.g., organic soil, hard water, etc), 

when using standard tests (e.g., AOAC, ASTM, etc) all deviations to the test methods 

should be reported;

 (xii) Test microorganisms employed, including identification of the specific strain 

(ATCC or other); 

 (xiii) Description of the test substance, including the percent of active ingredient;

 (xiv) Concentration or dilution of the product tested and how prepared;
8 

 (xv) Number of samples, batches and replicates tested;

 (xvi) Manufacture date of each product batch; 

 (xvii) Identification of all material or procedural options employed, where such 

choice is provided for or recommended in the test method selected (e.g., growth media, 

drying time for inoculated carriers, neutralization confirmation and/or subculture media, 

secondary subculturing);

 (xviii) Test exposure conditions (e.g., contact time, temperature, and relative 

humidity); 

 (xix) Complete reports of results obtained for each replication; 

 (xx) Any control data essential to establish the validity of the test;

 (xxi) Carrier counts;

 (xxii) Statistical treatment of the data;

 (xxiii) Conclusions;

 (xxiv) References;

 (xxv) Appendices, including study protocol and all raw data reports associated 

with the conduct of the study;

The applicant is encouraged to use the EPA’s standard efficacy report format, which 

may be found at http://www.epa.gov/oppad001/efficacystudystandards.htm.

 (2) Data for modifications of recommended methods. When recommended 

methods are modified for testing conducted to support specific claims and/or use 

patterns for a product, the protocol, identifying and describing each modification, should 

be provided with the study report. The applicant is encouraged to submit the proposed 

modification to the Agency for review and evaluation prior to initiation of the test. 

 (3) Data for other methods. When recommended methods, or modifications 

thereto, are not employed to develop efficacy data (such as actual in-use or many kinds 

of simulated-use testing), complete testing protocols should be submitted with the test 

reports. All materials and procedures employed in testing should be described in a 

manner consistent with original research reports published in technical or scientific 

journals. Where references to published reports or papers are made, copies or reprints 

of such references should be provided with the test reports. The applicant should 

submit the proposed testing protocols for in-use or simulated-use studies (with a 

proposed label to show the claims to be supported by the protocol) to the Agency for 

review and evaluation prior to initiation of the test. 
9 

 (g) References. The references in this paragraph may be consulted for additional background information. 

 (1) Guide Standard and Protocol for Testing Microbiological Water Purifiers. 

United States Environmental Protection Agency, Registration Division, Office of 

Pesticide Programs and Criteria and Standards Division, Office of Drinking Water, 

April 1987. 

 (2) Official Methods of Analysis of the Association of Official Analytical Chemists, 

Use-Dilution Methods, Chapter 6, Disinfectants; Current Edition. Association of 

Official Analytical Chemists (AOAC), 2200 Wilson Boulevard Arlington, VA 22201.

 (3) Suggested Ordinance and Regulations Covering Public Swimming Pools. 

Joint Committee on swimming Pools of the American Public Health Association, in 

Cooperation with the United States Public Health Service, 1964. The American 

Public Health Association, New York, NY. 

 (4) Standard Methods for the Examination of Water and Wastewater, Current 

Edition, Standard Methods Online: http://www.standardmethods.org.