Wisconsin DNR
Wisconsin environmental lab accreditation, DNR and NR 149.
Who accredits your lab in Wisconsin, how certification differs from registration, why a NELAP certificate does not carry over, and the initial calibration criteria written into NR 149.
At a glance
How environmental lab accreditation works in Wisconsin.
Wisconsin is not a NELAP state. The Department of Natural Resources accredits labs under its own rule, chapter NR 149, and bacteriological testing is certified separately by the Department of Agriculture, Trade and Consumer Protection.
State program (non-NELAP)
- Program
- Laboratory Accreditation Program, Wisconsin Department of Natural Resources. DNR accredits labs to test aqueous (non-potable water), non-aqueous and drinking water (potable water) samples for the agency’s covered programs.
- Rule
- Chapter NR 149, Wisconsin Administrative Code, repealed and recreated by CR 17-046, published March 1, 2021 and effective June 29, 2021
- Who needs it
- Labs that submit data to DNR for a covered program, or generate data DNR needs to determine compliance with one, for the fields of accreditation matching that data (NR 149.02 and 149.05). DNR describes the program as covering testing under the Clean Water Act, RCRA and the Safe Drinking Water Act.
- Certification or registration
- Certified labs can test compliance samples for other facilities. Registered labs test their own samples only. Registration is not available for safe drinking water and well testing analyses (NR 149.02(3)).
- Other agencies
- Bacteriological testing labs for a covered program are certified or approved by DATCP under ch. ATCP 77. Asbestos and radiological testing labs for a covered program must be certified or approved by EPA or DNR (NR 149.02).
- NELAP status
- Not a NELAP accreditation body. DNR states it does not recognize NELAP accreditations issued by other state or federal agencies.
- Out-of-state labs
- NR 149.08 lets DNR accept another state’s accreditation if its standards are substantially equivalent and that state accepts Wisconsin-accredited labs. DNR states there are no current reciprocity agreements with any state. Labs outside Wisconsin submit a letter of intent with an initial application.
The accreditation cycle
The NR 149 accreditation cycle.
The steps below summarize chapter NR 149 and the DNR program pages. Your certificate and DNR correspondence govern the specifics for your lab.
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Apply by field
Fields of accreditation have three tiers: matrix (aqueous, non-aqueous or drinking water), then technology or drinking water method, then analyte or analyte group (NR 149.13).
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Proficiency testing
At least one PT sample study per accreditation period for the fields on DNR’s required PT list (NR 149.22). DNR states acceptable PT results for tests that require one are due by August 31.
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On-site evaluations
Announced on-site evaluations once every three years, and also when a lab applies or changes location, ownership or key personnel (unless DNR waives it), to verify corrective action, or on suspected noncompliance (NR 149.29).
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Annual renewal
The accreditation period runs September 1 to August 31 (NR 149.15). DNR states accreditation ends on September 1 if renewal fees are not paid by August 31.
Initial calibration
What auditors check in your initial calibrations.
Wisconsin writes its own calibration criteria. NR 149.444 sets initial instrument calibration requirements, so a DNR evaluator can compare your curves to numbers in the code, not only to the method.
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.
Acceptance limits written into the code
NR 149.444 sets default limits by evaluation technique: a correlation coefficient of at least 0.995 for inorganic or 0.99 for organic analytes when linear regression is used, lowest point recovery within 80 to 120 percent for inorganics when residuals are used unless the method specifies otherwise, and a second-source ICV within 10 percent for inorganics or 20 percent for organics.
Source: Wis. Adm. Code NR 149.444 (Justia copy)
NR 149.444 also requires at least three nonzero standards (more for quadratic and cubic models) and lists relative standard deviation and residual recovery limits, and NR 149.446 sets separate continuing calibration requirements. Check the current code text for the limits that apply to your analytes and models.
Self-check
Are your initial calibrations ready for a Wisconsin 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.
Wisconsin specifics
Wisconsin puts the calibration numbers in the rule.
Labs that already hold NELAP accreditation elsewhere should plan for a full Wisconsin application. DNR states that it does not recognize NELAP accreditations issued by other state or federal agencies and that it has no current reciprocity agreements with any state, although NR 149.08 allows them.
The rule itself is specific. NR 149.444 sets correlation coefficient, relative standard deviation, residual recovery and second-source verification limits for initial calibrations, with separate limits for inorganic and organic analytes. Some yield to method criteria, but a DNR evaluator can test your records against the limits that apply.
The current chapter was recreated by CR 17-046 and took effect June 29, 2021. DNR’s program pages list no later revision to NR 149 as of October 2026, and accreditation still runs on a September 1 to August 31 year.
How WLTR helps
Calibration evidence ready for a Wisconsin DNR evaluation.
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 a DNR evaluator.
See how your own ICAL data looks when every analyte and model is laid out against the NR 149.444 limits.
Questions
Wisconsin accreditation FAQs
Is Wisconsin a NELAP state?
No. The Wisconsin DNR is not a NELAP accreditation body, and DNR states it does not recognize NELAP accreditations issued by other state or federal agencies.
Who accredits environmental labs in Wisconsin?
The Laboratory Accreditation Program of the Wisconsin Department of Natural Resources, under chapter NR 149, for aqueous, non-aqueous and drinking water testing for DNR’s covered programs. Bacteriological testing labs are certified or approved by DATCP under ch. ATCP 77.
What is the difference between certification and registration?
Certified labs can test compliance samples for other facilities. Registered labs test their own samples only. Registration is not available for safe drinking water and well testing analyses.
How often are labs evaluated and tested?
NR 149.29 calls for announced on-site evaluations once every three years, plus additional evaluations in specified circumstances. NR 149.22 requires at least one PT sample study per accreditation period, which runs September 1 to August 31.
Does Wisconsin have its own initial calibration rule?
Yes. NR 149.444 sets initial instrument calibration requirements, including correlation coefficient, relative standard deviation, residual recovery and second-source ICV limits. NR 149.446 covers continuing calibration.
Sources
Primary sources for this page.
- Wisconsin DNR, Laboratory Accreditation (opens in a new tab)
- Wisconsin DNR, laboratory accreditation applications (opens in a new tab)
- Wisconsin DNR, annual renewal (opens in a new tab)
- Wisconsin DNR, NR 149 code updates (opens in a new tab)
- Wis. Adm. Code ch. NR 149 (official PDF) (opens in a new tab)
- NR 149.444, initial instrument calibration (Justia copy) (opens in a new tab)
- NR 149.02, applicability (Justia copy) (opens in a new tab)
- TNI, NELAP recognized accreditation bodies (opens in a new tab)
- Wisconsin DNR, Laboratory Certification Program information (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 Wisconsin Department of Natural Resources. Spot something out of date? Tell us at admin@wltr.tech.
Before your next assessment
See your Wisconsin ICALs the way a DNR evaluator 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.
Request a demoHow the methodology works
Running environmental methods? See how WLTR works for environmental testing labs and water and wastewater utility labs.