4. On-Site Laboratory Audit 4.1 On-Site Laboratory Audit Team The certification program manager should establish one or more teams of certification officers and auditors to audit aboratories. It is the responsibility of these teams to perform the on-site laboratory audits, review the laboratory pt data, and make recommendations to the ca concerning the certification status of the laboratories Team members should be experienced professionals, hold at least a bachelor's degree or equivalent education/experience in the discipline(chemistry, radiochemistry, microbiology or a related field) for which they certify, and have recent laboratory experience Team members should also have experience in laboratory evaluation and quality assurance, be familiar with the drinking ater regulations and data reduction and reporting techniques, be technically conversant with the analytical techniques being evaluated, and be able to communicate effectively, both orally and in writing The on-site team should include at least one person knowledgeable in each area being audited(e.g, inorganic and organic chemistry, radiochemistry, and microbiology) COs need to successfully complete the appropriate EPA laboratory certification course. In addition, there should be a mechanism for COs to receive periodic training regarding newly promulgated regulations, newly adopted certification criteria, and new methods. This could be done by auditing the epa CO Training Course and/or attending the required annual Regional and State CO Meetings. 4.2 Third Party Auditors Certification programs may employ third party auditors who meet all of the qualifications listed above. In areas where experience does not exist within the certification team(e.g, asbestos ), outside expert assistance may be obtained in the needed areas to assist the on-site team. Outside experts who have not attended the epa certification officer training should be accompanied by a certification officer. Although these third parties may be used to assist EPA or State certification officers, they have no authority for certification decisions and they may not make final certification decisions. These decisions rest with the epa or the state When using third party experts, it is critical to avoid conflicts of interest. a third party auditor who in any way stand to benefit by the certification status of the laboratory audited may not be used 5. Plans for Certification of laboratories The certification program manager should develop plans for certifying drinking water laboratories under her/his authority. Written plans should include the following Documentation of certification authority and certification officers and their education/experience Schedules of laboratories to be audited pecific types of analyses to be examined; Protocol to be followed Strategy for assessing laboratory performance(e.g, PTs, data audits, etc. ) Plans for providing technical assistance to laboratories which need upgrading 6. Principal State Laboratories To receive and retain primacy, the State must(40 CFR 142. 10(b) (4) have available laboratory facilities capable of performing analytical measurements for all the federally mandated contaminants specified in the State Primary Drinking Water Regulations. This laboratory or laboratories are considered the Principal State Laboratory System and must be certified by EPa 7. Certification Process The certification process begins when the laboratory director makes a formal request in writing to the certification authority to be certified. This application may be one of the following I-2
III-2 4. On-Site Laboratory Audit 4.1 On-Site Laboratory Audit Team The certification program manager should establish one or more teams of certification officers and auditors to audit laboratories. It is the responsibility of these teams to perform the on-site laboratory audits, review the laboratory PT data, and make recommendations to the CA concerning the certification status of the laboratories. Team members should be experienced professionals, hold at least a bachelor's degree or equivalent education/experience in the discipline (chemistry, radiochemistry, microbiology or a related field) for which they certify, and have recent laboratory experience. Team members should also have experience in laboratory evaluation and quality assurance, be familiar with the drinking water regulations and data reduction and reporting techniques, be technically conversant with the analytical techniques being evaluated, and be able to communicate effectively, both orally and in writing. The on-site team should include at least one person knowledgeable in each area being audited (e.g., inorganic and organic chemistry, radiochemistry, and microbiology). COs need to successfully complete the appropriate EPA laboratory certification course. In addition, there should be a mechanism for COs to receive periodic training regarding newly promulgated regulations, newly adopted certification criteria, and new methods. This could be done by auditing the EPA CO Training Course and/or attending the required annual Regional and State CO Meetings. 4.2 Third Party Auditors Certification programs may employ third party auditors who meet all of the qualifications listed above. In areas where experience does not exist within the certification team (e.g., asbestos), outside expert assistance may be obtained in the needed areas to assist the on-site team. Outside experts who have not attended the EPA certification officer training should be accompanied by a certification officer. Although these third parties may be used to assist EPA or State certification officers, they have no authority for certification decisions and they may not make final certification decisions. These decisions rest with the EPA or the State. When using third party experts, it is critical to avoid conflicts of interest. A third party auditor who in any way stands to benefit by the certification status of the laboratory audited may not be used. 5. Plans for Certification of Laboratories The certification program manager should develop plans for certifying drinking water laboratories under her/his authority. Written plans should include the following: • Documentation of certification authority and certification officers and their education/experience; • Schedules of laboratories to be audited; • Specific types of analyses to be examined; • Protocol to be followed; • Strategy for assessing laboratory performance (e.g., PTs, data audits, etc.); • Plans for providing technical assistance to laboratories which need upgrading. 6. Principal State Laboratories To receive and retain primacy, the State must (40 CFR 142.10(b)(4)) have available laboratory facilities capable of performing analytical measurements for all the federally mandated contaminants specified in the State Primary Drinking Water Regulations. This laboratory or laboratories are considered the Principal State Laboratory System and must be certified by EPA. 7. Certification Process The certification process begins when the laboratory director makes a formal request in writing to the certification authority to be certified. This application may be one of the following:
A request for first-time certification for microbiology, chemistry, or radiochemistry; A request for certification to analyze additional or newly regulated contaminants; a request to reapply for certification after correction of deficiencies which resulted in the downgrading/revocation of certification status The response to a formal application for any of the above requests should be given within 30 days. At this time a mutually agreeable date and time should be set for the on-site laboratory audit. Subsequent audits may be initiated by the Ca or the laboratory A recommended protocol for conducting these audits is given in Appendix B Drinking water laboratories should specifically state that they plan to analyze drinking water samples when they request certification. If a laboratory has not been analyzing drinking water samples and does not plan to analyze drinking water samples, OGWDW, the Region or State may choose not to expend the resources to renew their certification 8. Types of Certification After review of PT sample results and an on-site visit, the certification authority should provide a written report within 45 days and classify the laboratory for each contaminant or group of contaminants according to the following rating scheme. 8.1 Certified-a laboratory that meets the regulatory performance criteria as explained in this manual and all other pplicable regulatory requirements 8.2 Provisionally Certified-a laboratory that has deficiencies but demonstrates its ability to consistently produce valid data within the acceptance limits specified in the NPDWR, and within the policy required by their certification authority. A provisionally certified laboratory may analyze drinking water samples for compliance purposes, if the said clients are notified of its downgraded status in writing, on any report. Provisional certification may not be given if the evaluation team believes that the laboratory cannot perform an analysis within the acceptance limits specified in the regulations 8.3 Not Certiffied-a laboratory that possesses deficiencies and, in the opinion of the Certification Authority, cannot consistently produce valid data 8.4 Interim Certification- interim certification may be granted in certain circumstances when it is impossible or unnecessary to perform an on-site audit. Interim certification status may be granted if, for example, the Ca determines that the laboratory has the appropriate instrumentation, is using the approved methods, has adequately trained personnel to perform the analyses, and has satisfactorily analyzed PT samples, if available, for the contaminants in question. The CO should perform an on-site audit as soon as possible but no later than three years. An example of a situation where this type of certification is warranted would be a laboratory that has requested certification for the analysis of additional analytes that involve a method for which it already has certification. The Co should review the laboratory's quality control data before granting this type of certification 9. Drinking water laboratories For the purpose of certification, any laboratory which analyzes drinking water compliance samples is considered a drinking water laboratory. This includes Federal laboratories that analyze compliance samples and any laboratories that analyze compliance samples for Federal facilities. All such laboratories must(40 CFR 141.21,.23, 24, 25)be certified by the State or EPA. If requested by the State, a Region may certify Federal laboratories in its Region. The Region certifies individual laboratories on Tribal Nation lands, when requested by the tribal chairperson. These laboratories must meet the criteria for certification as specified in the NPdwr. I-3
III-3 • A request for first-time certification for microbiology, chemistry, or radiochemistry; • A request for certification to analyze additional or newly regulated contaminants; • A request to reapply for certification after correction of deficiencies which resulted in the downgrading/revocation of certification status. The response to a formal application for any of the above requests should be given within 30 days. At this time a mutually agreeable date and time should be set for the on-site laboratory audit. Subsequent audits may be initiated by the CA or the laboratory. A recommended protocol for conducting these audits is given in Appendix B. Drinking water laboratories should specifically state that they plan to analyze drinking water samples when they request certification. If a laboratory has not been analyzing drinking water samples and does not plan to analyze drinking water samples, OGWDW, the Region or State may choose not to expend the resources to renew their certification. 8. Types of Certification After review of PT sample results and an on-site visit, the certification authority should provide a written report within 45 days and classify the laboratory for each contaminant or group of contaminants according to the following rating scheme: 8.1 Certified - a laboratory that meets the regulatory performance criteria as explained in this manual and all other applicable regulatory requirements. 8.2 Provisionally Certified - a laboratory that has deficiencies but demonstrates its ability to consistently produce valid data within the acceptance limits specified in the NPDWR, and within the policy required by their certification authority. A provisionally certified laboratory may analyze drinking water samples for compliance purposes, if the said clients are notified of its downgraded status in writing, on any report. Provisional certification may not be given if the evaluation team believes that the laboratory cannot perform an analysis within the acceptance limits specified in the regulations. 8.3 Not Certified - a laboratory that possesses deficiencies and, in the opinion of the Certification Authority, cannot consistently produce valid data. 8.4 Interim Certification - interim certification may be granted in certain circumstances when it is impossible or unnecessary to perform an on-site audit. Interim certification status may be granted if, for example, the CA determines that the laboratory has the appropriate instrumentation, is using the approved methods, has adequately trained personnel to perform the analyses, and has satisfactorily analyzed PT samples, if available, for the contaminants in question. The CO should perform an on-site audit as soon as possible but no later than three years. An example of a situation where this type of certification is warranted would be a laboratory that has requested certification for the analysis of additional analytes that involve a method for which it already has certification. The CO should review the laboratory's quality control data before granting this type of certification. 9. Drinking Water Laboratories For the purpose of certification, any laboratory which analyzes drinking water compliance samples is considered a drinking water laboratory. This includes Federal laboratories that analyze compliance samples and any laboratories that analyze compliance samples for Federal facilities. All such laboratories must (40 CFR 141.21, .23, .24, .25) be certified by the State or EPA. If requested by the State, a Region may certify Federal laboratories in its Region. The Region certifies individual laboratories on Tribal Nation lands, when requested by the tribal chairperson. These laboratories must meet the criteria for certification as specified in the NPDWR
The Regions use the criteria, procedures, and mechanism as specified in the NPdWr and this manual in their decisions to certify municipal or private drinking water laboratories in non-primacy states 10. Other Considerations for Laboratory Certification 10.1 Laboratory Personnel The laboratory should have sufficient supervisory and other personnel, with the necessary education, training, technical know ledge, and experience for their assigned functions 10.2 Laboratory Director/Manager or Technical Director The laboratory director/manager should be a qualified professional with the technical education and experience, and managerial capability commensurate with the size/type of the laboratory. The laboratory director/manager is ultimately responsible for ensuring that all laboratory personnel have demonstrated proficiency for their assigned functions and that all data reported by the laboratory meet the required quality assurance( QA)criteria and regulatory requirements 10.3 Quality Assurance Manager The QA manager should be independent from the laboratory management, if possible, and have direct access to the highest level of management. The QA manager should have a bachelors degree in science, training in quality assurance principles commensurate with the size and sophistication of the laboratory, and at least one year of experience in quality assurance. The QA manager should have at least a working knowledge of the statistics involved in quality control of laboratory analysis and a basic understanding of the methods which the laboratory employs 11. Laboratory Quality Assurance Plan All laboratories analyzing drinking water compliance samples must adhere to any required QC procedures specified in the methods. This is to ensure that routinely generated analytical data are scientifically valid and defensible, and are of known and acceptable precision and accuracy. To accomplish these goals, each laboratory should(EPa Order 5360.1 A2)prepare a written description of its QA activities(a QA plan). It is the responsibility of the QA manager to keep the QA plan up to date. All laboratory personnel need to be familiar with the contents of the Qa plan. This plan should b submitted to the auditors for review prior to the on-site visit or should be reviewed as part of the on-site visit The laboratory Qa plan should be a separately prepared text. However, documentation for many of the listed Qa plar tems may be made by reference to appropriate sections of this manual, the laboratory's standard operating procedures, (SOPs)or other literature(e.g, promulgated methods, Standard Methods for the Examination ofWater and Wastewater, etc. ) The QA Plan should be updated at least annually(EPA Order 5360.1 A2) At a minimum, the following items should be addressed in each Qa plan: 11. I Laboratory organization and responsibility include a chart or table showing the laboratory organization and lines of responsibility, including QA managers; list the key individuals who are responsible for ensuring the production of valid measurements and the routine assessment of measurement systems for precision and accuracy(e.g, who is responsible for internal audits and reviews of the implementation of the plan and its requirements); reference the job descriptions of the personnel and describe training to keep personnel updated on regulations and methodology, and document that laboratory personnel have demonstrated ncy for the methods they perform 11.2 Process used to identify clients' Data Qnality Objectives 11.3 SOPs with dates of last revision The laboratory should maintain SOPs that accurately reflect all phases of current laboratory activities keep a list of SoPs ensure that current copies of SoPs are in the laboratory and in the Qa managers files nsure that SOPs are reviewed annually and revised as changes are made; ensure that SOPs have signature pages and revisions dated I-4
III-4 The Regions use the criteria, procedures, and mechanism as specified in the NPDWR and this manual in their decisions to certify municipal or private drinking water laboratories in non-primacy states. 10. Other Considerations for Laboratory Certification 10.1 Laboratory Personnel The laboratory should have sufficient supervisory and other personnel, with the necessary education, training, technical knowledge, and experience for their assigned functions. 10.2 Laboratory Director/Manager or Technical Director The laboratory director/manager should be a qualified professional with the technical education and experience, and managerial capability commensurate with the size/type of the laboratory. The laboratory director/manager is ultimately responsible for ensuring that all laboratory personnel have demonstrated proficiency for their assigned functions and that all data reported by the laboratory meet the required quality assurance (QA) criteria and regulatory requirements. 10.3 Quality Assurance Manager The QA manager should be independent from the laboratory management, if possible, and have direct access to the highest level of management. The QA manager should have a bachelor's degree in science, training in quality assurance principles commensurate with the size and sophistication of the laboratory, and at least one year of experience in quality assurance. The QA manager should have at least a working knowledge of the statistics involved in quality control of laboratory analysis and a basic understanding of the methods which the laboratory employs. 11. Laboratory Quality Assurance Plan All laboratories analyzing drinking water compliance samples must adhere to any required QC procedures specified in the methods. This is to ensure that routinely generated analytical data are scientifically valid and defensible, and are of known and acceptable precision and accuracy. To accomplish these goals, each laboratory should (EPA Order 5360.1 A2) prepare a written description of its QA activities (a QA plan). It is the responsibility of the QA manager to keep the QA plan up to date. All laboratory personnel need to be familiar with the contents of the QA plan. This plan should be submitted to the auditors for review prior to the on-site visit or should be reviewed as part of the on-site visit. The laboratory QA plan should be a separately prepared text. However, documentation for many of the listed QA plan items may be made by reference to appropriate sections of this manual, the laboratory's standard operating procedures, (SOPs) or other literature (e.g., promulgated methods, Standard Methods for the Examination of Water and Wastewater, etc.). The QA Plan should be updated at least annually (EPA Order 5360.1 A2). At a minimum, the following items should be addressed in each QA plan: 11.1 Laboratory organization and responsibility • include a chart or table showing the laboratory organization and lines of responsibility, including QA managers; • list the key individuals who are responsible for ensuring the production of valid measurements and the routine assessment of measurement systems for precision and accuracy (e.g., who is responsible for internal audits and reviews of the implementation of the plan and its requirements); • reference the job descriptions of the personnel and describe training to keep personnel updated on regulations and methodology, and document that laboratory personnel have demonstrated proficiency for the methods they perform. 11.2 Process used to identify clients' Data Quality Objectives 11.3 SOPs with dates of last revision C The laboratory should maintain SOPs that accurately reflect all phases of current laboratory activities C keep a list of SOPs C ensure that current copies of SOPs are in the laboratory and in the QA Managers files; C ensure that SOPs are reviewed annually and revised as changes are made; C ensure that SOPs have signature pages and revisions dated
11. 4 Field sampling procedures describe the process used to identify sample collectors, sampling procedures and locations, required preservation, proper containers, correct sample container cleaning procedures, sample holding times from collection to analysis, and sample shipping and storage conditions; ensure that appropriate forms are legibly filled out in indelible ink or hard copies of electronic data are available. See Chapters Iv, v, and vi for specific items to be included describe how samples are checked when they arrive for proper containers and temperature and how samples are checked for proper preservation(e.g, pH, chlorine residual) before analysis; ensure that sampling protocol is written and available to samplers 11.5 Laboratory sample receipt and handling procedures bound laboratory note books, if used, should be filled out in ink; entries dated and signed (A secure, passwo protected, electronic data base is acceptable) tore unprocessed and processed samples at the proper temperature, isolated from laboratory contaminants standards and highly contaminated samples and, sometimes, each other; holding times may not be exceeded maintain integrity of all samples, (e. g, by tracking samples from receipt by laboratory through analysis to require Chain-of-Custody procedures for samples likely to be the basis for an enforcement action(see Appendix specify criteria for rejection of samples which do not meet shipping, holding time and/or preservation requirements and procedures for notification of sample originators 11.6 Instrument calibration procedures (may reference SOP) specify type of calibration used for each method and frequency of use, escribe calibration standards source, age, storage, labeling perform data comparability checks use control charts and for radiochemistry, report counting errors with their confidence levels 11. 7 Analytical procedures(may reference SOP) cite complete method manual; describe quality control procedures required by the methods that need to be followe 11.8 Data reduction, validation, reporting and verification (may reference SOP) describe data reduction process: method of conversion of raw data to mg/L, picocuries/L, coliforms/100 mL describe data validation process; describe reporting procedures, include procedures and format; describe data verification process for radiochemistry, describe reporting of counting uncertainties and confidence levels describe procedure for data corrections. 11.9 Type of quality control (@c) checks and the frequency of their use(see Chapters /v,and vi). (may reference SO Parameters for chemistry and radiochemistry should include or reference instrument performance check standards frequency and acceptability of method detection limit(MDl) calculations frequency and acceptability of demonstration of low level capabilit calibration. internal and surrogate standards laboratory reagent blank, field reagent blank and trip blank field and laboratory matrix replicates; quality control and proficiency testing samples laboratory fortified blank and laboratory fortified sample matrix replicates; I-5
III-5 11.4 Field sampling procedures • describe the process used to identify sample collectors, sampling procedures and locations, required preservation, proper containers, correct sample container cleaning procedures, sample holding times from collection to analysis, and sample shipping and storage conditions; • ensure that appropriate forms are legibly filled out in indelible ink or hard copies of electronic data are available. See Chapters IV, V, and VI for specific items to be included; • describe how samples are checked when they arrive for proper containers and temperature and how samples are checked for proper preservation (e.g., pH, chlorine residual) before analysis; • ensure that sampling protocol is written and available to samplers. 11.5 Laboratory sample receipt and handling procedures • bound laboratory note books, if used, should be filled out in ink; entries dated and signed (A secure, password protected, electronic data base is acceptable); • store unprocessed and processed samples at the proper temperature, isolated from laboratory contaminants, standards and highly contaminated samples and, sometimes, each other; holding times may not be exceeded; • maintain integrity of all samples, (e.g., by tracking samples from receipt by laboratory through analysis to disposal); • require Chain-of-Custody procedures for samples likely to be the basis for an enforcement action (see Appendix A); • specify criteria for rejection of samples which do not meet shipping, holding time and/or preservation requirements and procedures for notification of sample originators. 11.6 Instrument calibration procedures (may reference SOP) • specify type of calibration used for each method and frequency of use; • describe calibration standards' source, age, storage, labeling; • perform data comparability checks; • use control charts and for radiochemistry, report counting errors with their confidence levels. 11. 7 Analytical procedures (may reference SOP) • cite complete method manual; • describe quality control procedures required by the methods that need to be followed. 11.8 Data reduction, validation, reporting and verification (may reference SOP) • describe data reduction process: method of conversion of raw data to mg/L, picocuries/L, coliforms/100 mL, etc.; • describe data validation process; • describe reporting procedures, include procedures and format; • describe data verification process; • for radiochemistry, describe reporting of counting uncertainties and confidence levels; • describe procedure for data corrections. 11.9 Type of quality control (QC) checks and the frequency of their use (see Chapters IV, V and VI).(may reference SOP) Parameters for chemistry and radiochemistry should include or reference: • instrument performance check standards; • frequency and acceptability of method detection limit (MDL) calculations; • frequency and acceptability of demonstration of low level capability; • calibration, internal and surrogate standards; • laboratory reagent blank, field reagent blank and trip blank; • field and laboratory matrix replicates; • quality control and proficiency testing samples; • laboratory fortified blank and laboratory fortified sample matrix replicates; • initial demonstration of method capability
use of control charts. qualitative identification/confirmation of contaminants Parameters for microbiology should include or reference positive and negative culture controls confirmation/verification of presumptive total coliform positive samples sterility controls 11 10 List schedules of internal and external system and data quality audits and inter laboratory comparisons(may reference SOP) Il II Preventive maintenance procedures and schedules describe location of instrument manuals and schedules and documentation of routine equipment maintenance escribe availability of instrument spare parts in the laboratory list any maintenance contracts in place. 11 12 Corrective action contingencies describe response to obtaining unacceptable results from analysis of PT samples and from internal Qc checks; ame persons responsible for the various corrective actions describe how corrective actions taken are documented 11.13 Record keeping procedures describe procedures and documentation of those procedures list length of storage, media type (electronic or hard copy); describe security policy of electronic databases; all electronic data should have software support so it may be regenerated If a particular item is not relevant, the Qa plan should state this and provide a brief explanation. A laboratory Qa plan should be responsive to the above items while remaining brief and easy to follow. Minimizing paperwork, while 12. Chain-of-Custody Procedures Certified laboratories, when requested to process a sample for possible legal action against a supplier, should use an adequate chain-of-custody procedure. An example of such a procedure is found in Appendix A. The State or Region should seek input from its attorney general's office to ensure that the laboratorys procedures are adequate. The procedure used should be documented 13. Requirements for Maintaining Certification Status 13.I Proficiency Testing(PT) Samples At least annually drinking water laboratories certified for chemical contaminants must satisfactorily analyze a Pt sample to maintain certification(40CFR 141 23()(3)(1), 141.24(h(17)(i)(A)and 141.89(a)(1)(i). PT samples should be analyzed in the same manner as routine samples. Laboratories must acquire the Pt sample from a supplier acceptable to the appropriate certification authority. If the certified laboratory does not analyze the pt sample within the acceptance limits specified in the regulations, or within policy described by their certifying authority, the certifying authority should follow the procedure discussed in the section entitled, Criteria and Procedures for Downgrading/Revoking Certification Status. If a laboratory wishes to be certified for a contaminant by more than one method, it must (40CFR 141.23(k)(3)(ii), 141.24(h)(17)(I(A)and 141.89(a(1)() analyze the PT samples by each method for which it wishes to be certified. The methods listed on the laboratory's certification certificate must be the methods by which the PT samples were analyzed. II-6
III-6 • use of control charts; • qualitative identification/confirmation of contaminants. Parameters for microbiology should include or reference: • positive and negative culture controls; • confirmation/verification of presumptive total coliform positive samples; • sterility controls; • proficiency testing and quality control samples. 11.10 List schedules of internal and external system and data quality audits and inter laboratory comparisons (may reference SOP) 11.11 Preventive maintenance procedures and schedules • describe location of instrument manuals and schedules and documentation of routine equipment maintenance; • describe availability of instrument spare parts in the laboratory; • list any maintenance contracts in place. 11.12 Corrective action contingencies • describe response to obtaining unacceptable results from analysis of PT samples and from internal QC checks; • name persons responsible for the various corrective actions; • describe how corrective actions taken are documented; 11.13 Record keeping procedures • describe procedures and documentation of those procedures; • list length of storage, media type (electronic or hard copy); • describe security policy of electronic databases; • all electronic data should have software support so it may be regenerated. If a particular item is not relevant, the QA plan should state this and provide a brief explanation. A laboratory QA plan should be responsive to the above items while remaining brief and easy to follow. Minimizing paperwork, while improving dependability and quality of data, are the intended goals. 12. Chain-of-Custody Procedures Certified laboratories, when requested to process a sample for possible legal action against a supplier, should use an adequate chain-of-custody procedure. An example of such a procedure is found in Appendix A. The State or Region should seek input from its attorney general's office to ensure that the laboratory's procedures are adequate. The procedure used should be documented. 13. Requirements for Maintaining Certification Status 13.1 Proficiency Testing (PT) Samples At least annually drinking water laboratories certified for chemical contaminants must satisfactorily analyze a PT sample to maintain certification (40CFR 141.23(k)(3)(i),141.24(h)(17)(i)(A) and 141.89(a)(1)(i)). PT samples should be analyzed in the same manner as routine samples. Laboratories must acquire the PT sample from a supplier acceptable to the appropriate certification authority. If the certified laboratory does not analyze the PT sample within the acceptance limits specified in the regulations, or within policy described by their certifying authority, the certifying authority should follow the procedure discussed in the section entitled, "Criteria and Procedures for Downgrading/Revoking Certification Status." If a laboratory wishes to be certified for a contaminant by more than one method, it must (40CFR 141.23(k)(3)(ii),141.24(h)(17)(i)(A) and 141.89(a)(1)(i)) analyze the PT samples by each method for which it wishes to be certified. The methods listed on the laboratory's certification certificate must be the methods by which the PT samples were analyzed