Ohio EPA Laboratory Certification
Ohio environmental lab certification, Ohio EPA and its 2025 manuals.
Who certifies drinking water labs in Ohio, how surveys, proficiency testing and renewal work, when NELAP or out-of-state labs can be accepted, and where Ohio sets calibration requirements.
At a glance
How environmental lab certification works in Ohio.
Ohio is not a NELAP accreditation body. Ohio EPA certifies laboratories that analyze public drinking water under its own rules in Ohio Administrative Code Chapter 3745-89, and its Voluntary Action Program has separate laboratory rules.
Drinking water lab certification
- Drinking water program
- Laboratory Certification Section, Ohio EPA Division of Drinking and Ground Waters, as shown on Ohio EPA’s laboratory certification page and guidance.
- Rules
- Ohio Adm. Code Chapter 3745-89. Rules 3745-89-02, -04, -05 and -12 are effective July 7, 2025, and 3745-89-03 is effective July 23, 2026.
- Who needs it
- Drinking water analyses covered by 3745-89-02 must be performed by a certified Ohio laboratory, by an analyst designated on its certificate, or by the State Principal Laboratory or another laboratory accepted under 3745-89-12.
- Analysts
- Analysts are certified at a laboratory only for the methods noted on their certificate, and an analyst must undergo a survey to add drinking water methods.
- NELAP status
- Not a NELAP accreditation body as of October 2026. NELAP accreditation can support an application for alternate acceptance under 3745-89-12.
- Out-of-state labs
- Accepted only under the conditions in 3745-89-02(D), such as analytes for which no Ohio laboratory is certified, insufficient laboratory capacity, or samples from an out-of-state system that supplies a consecutive water system in Ohio. Chapter 3745-90 analytes are excluded.
- Voluntary Action Program
- Under rules effective February 16, 2025, a VAP laboratory is an accredited laboratory or a laboratory certified under the October 17, 2019 version of 3745-300-04. Certified labs keep voluntary action documents and data for at least ten years after submitting analyses.
The accreditation cycle
The Ohio EPA certification cycle.
The steps below summarize Chapter 3745-89 and Ohio EPA’s certification guidance for drinking water labs. Your certificate and Ohio EPA correspondence govern the specifics for your lab.
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Apply with a quality assurance plan
Submit a complete application and a quality assurance plan acceptable to the director (3745-89-03).
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Proficiency testing
Proficiency test samples analyzed at least annually for every contaminant by each method, and acceptable results within the past twelve months in at least one PT for each regulated contaminant (3745-89-03 and -05).
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Surveys
Demonstrate acceptable performance during the initial and subsequent surveys. Ohio EPA issues the survey report within forty-five days, and certified labs must allow surveys, including unannounced surveys.
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Renewal
Ohio EPA guidance states certificates are valid for no more than three years. Renewal applications are due no sooner than 120 days and no later than 30 days before expiration (3745-89-04).
Initial calibration
What auditors check in your initial calibrations.
Ohio’s certification rule does not set calibration criteria itself. Rule 3745-89-03 requires labs to follow Ohio EPA’s 2025 laboratory manuals, and the chemistry manual carries method-level calibration requirements.
A range that brackets what you report
The lowest standard should sit at or below your reporting limit and the highest at or above the top concentration you report. Results outside the calibrated range need to be qualified.
Error at the low end, not r² alone
A correlation coefficient of 0.999 can still hide a low standard that back-calculates 30 percent off. Auditors look at relative error, especially at the lowest levels.
Records that rebuild the curve
Raw responses, the model and weighting used, any excluded points with the reason, and the verification that followed. An auditor should be able to reconstruct every initial calibration from the record.
Calibration written into the Ohio manual
For fluoride by ion selective electrode, the 2025 chemistry manual calls for a 2-point calibration (0.5 and 5.0 mg/L) at the start of each eight-hour shift in which drinking water samples are run, a 1.0 mg/L verification standard within 10 percent of the true value, and a slope between 95.0 and 105.0 percent.
Source: Ohio EPA Laboratory Manual for Chemical Analyses of Public Drinking Water 2025, Fluoride Analysis by Ion-Selective Electrode Method
Ohio EPA also publishes the Laboratory Manual for the Microbiological Analyses of Public Drinking Water 2025, which 3745-89-03 also names. Check the current editions of both manuals before a survey.
Self-check
Are your initial calibrations ready for an Ohio assessment?
Tick what your lab could show an auditor today. Nothing you select is saved or sent anywhere.
6Checks to work through
Select each item your lab could show an auditor today.
A self-assessment to help you prepare, not a compliance determination.
Ohio specifics
Ohio surveys drinking water labs against its own manuals.
Ohio rewrote its drinking water laboratory rules in 2025. Most of Chapter 3745-89 took effect July 7, 2025, rule 3745-89-03 was amended effective July 23, 2026, and the rule now points to 2025 editions of Ohio EPA’s chemistry and microbiology laboratory manuals. A surveyor compares your records to those manuals, method by method.
NELAP accreditation is not a substitute for an Ohio certificate, but it can support alternate acceptance under 3745-89-12. A lab certified by USEPA, NELAP or another program acceptable to the director for drinking water submits, among other items, its most recent survey report and its two most recent PT evaluations. Chapter 3745-90 analytes are excluded, and out-of-state labs must also meet a condition in 3745-89-02(D).
Labs supporting Ohio’s Voluntary Action Program work under a separate chapter. Since February 16, 2025, Ohio Adm. Code 3745-300-01 defines an accredited laboratory, for constituents other than asbestos, as one holding valid accreditation from an accreditation body recognized by NELAP.
How WLTR helps
Calibration evidence ready for an Ohio EPA survey.
WLTR independently reviews the calibration your instrument software produced. Your analyst still makes the final call. What changes is that the evidence is complete, consistent across analysts, and ready before the auditor asks for it.
- Each analyte reviewed one at a time in the instrument software.
- The model and weighting are whatever the batch was processed with.
- r² is the number most people look at, even though it does not measure error at the low end.
- QA signs off without an independent check on the curve.
- Every analyte and every candidate model side by side in the Calibration Intelligence dashboard.
- Diagnostics run automatically and the best fit curve is identified, with the reasons recorded.
- Relative error at every level, including the lowest standard, shown on one screen.
- A traceable record your QA manager can review, sign and hand to an Ohio EPA surveyor.
See how your own ICAL data looks when every analyte and model is laid out for review.
Questions
Ohio accreditation FAQs
Is Ohio a NELAP state?
No. Ohio EPA is not on TNI’s list of NELAP accreditation bodies as of October 2026. It certifies drinking water labs under its own rules in Ohio Adm. Code Chapter 3745-89.
Who certifies drinking water labs in Ohio?
The Laboratory Certification Section of Ohio EPA, under Ohio Adm. Code Chapter 3745-89. Analysts are certified at the laboratory for the methods noted on their certificate.
Can a NELAP-accredited or out-of-state lab be accepted?
Possibly, through alternate acceptance under 3745-89-12, based on USEPA, NELAP or another acceptable certification for drinking water, with submissions that include the most recent survey report and the two most recent PT evaluations. Out-of-state labs must also meet a condition in 3745-89-02(D).
How long does Ohio certification last?
Ohio EPA states that certificates are valid for no more than three years from issuance. Renewal applications are due 120 to 30 days before expiration, and a timely, complete application extends certification until the renewal survey is completed.
Does Ohio have its own calibration rules?
The rule itself does not set calibration criteria, but it requires labs to follow Ohio EPA’s 2025 chemistry manual, which sets method-level requirements such as the fluoride calibration frequency, verification standard and slope limits.
Sources
Primary sources for this page.
- TNI, NELAP recognized accreditation bodies (opens in a new tab)
- Ohio Adm. Code 3745-89-02, analyses requiring laboratory certification (opens in a new tab)
- Ohio Adm. Code 3745-89-03, procedure for laboratory certification (effective July 23, 2026) (opens in a new tab)
- Ohio Adm. Code 3745-89-12, alternate acceptance (Cornell LII copy) (opens in a new tab)
- Ohio EPA, Obtaining Laboratory Certification (opens in a new tab)
- Ohio EPA, Issuance of Laboratory Certification (opens in a new tab)
- Ohio EPA Laboratory Manual for Chemical Analyses of Public Drinking Water 2025 (opens in a new tab)
- Ohio Adm. Code 3745-300-01, Voluntary Action Program definitions (opens in a new tab)
This page summarizes public program information to help labs prepare. Requirements change, and the agency’s current rules and guidance always take precedence. WLTR is not affiliated with or endorsed by the Ohio Environmental Protection Agency. Spot something out of date? Tell us at admin@wltr.tech.
Before your next assessment
See your Ohio ICALs the way a surveyor will.
Bring a recent initial calibration. We will walk you through every analyte and candidate model in the Calibration Intelligence dashboard, the best fit, and the record your QA manager would sign.
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