Iowa DNR Laboratory Certification
Iowa environmental lab certification, the DNR and Chapter 83.
Who certifies your lab in Iowa, which program areas Chapter 83 covers, how out-of-state labs qualify, and what auditors look for in your initial calibrations.
At a glance
How environmental lab certification works in Iowa.
Iowa is not a NELAP state. The Iowa Department of Natural Resources certifies labs that report environmental compliance data to it, under its own rule, across drinking water, wastewater and land quality programs.
State program (non-NELAP)
- Program
- Environmental laboratory certification, Iowa Department of Natural Resources. The DNR contracts with the State Hygienic Laboratory at the University of Iowa for technical assistance and auditing services.
- Legal basis
- 567 IAC Chapter 83, Laboratory Certification, adopted in its current form effective June 18, 2025. The chapter incorporates the DNR’s Manual for the Certification of Laboratories Analyzing Environmental Samples by reference.
- Who needs it
- Laboratories reporting environmental compliance data to the DNR. Methods must be promulgated or approved by EPA or by the department (83.5(1)).
- Program areas
- Clean Water Act (wastewater, non-potable water), Safe Drinking Water Act, municipal biosolids, solid waste, contaminated sites and underground storage tanks. SW-846 methods are offered in the solid waste and contaminated sites programs.
- Drinking water
- Certified by the DNR under the same chapter. The State Hygienic Laboratory serves as the state primacy laboratory under the Safe Drinking Water Act.
- Out-of-state labs
- Reciprocal certification may be granted, but a lab must first be certified by its home state if that state has a program for the area. The DNR also accepts third-party accreditation from a state NELAP accreditation authority (83.3(3)).
- NELAP status
- Not a NELAP accreditation body as of October 2026. Iowa certifies to its own rule, but PT samples must come from a NELAP accredited provider.
The accreditation cycle
From application to renewal.
The steps below summarize 567 IAC Chapter 83 and the DNR program page. Your certificate and DNR correspondence govern the specifics for your lab.
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Apply by program area
Submit a complete application and fee for each program area. The DNR will not conduct the on-site audit until both are received.
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Proficiency testing
Satisfactory PT results at least once every 12 months for each analyte by each method in each program area, using a NELAP accredited PT provider (83.5(2)).
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Site audits
A periodic site audit by the DNR or its designee at least every two years (83.5(5)).
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Two-year renewal
Certification is valid for no more than two years from issuance (83.5(6)). Renewal applications are due at least 60 days before expiration (83.3(1)).
Initial calibration
What auditors check in your initial calibrations.
Iowa’s rule requires certified labs to run and document calibration curves, and the DNR certification manual points back to each method for calibration and quality control. Auditors start with the method, then check that the record supports it.
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.
Curves run, documented and verified
567 IAC 83.5(4) lists running and documenting calibration curves among a certified lab’s annual requirements. The DNR manual’s wastewater chapter says calibration must follow the method and that daily curve checks should fall within plus or minus 20 percent or the system must be recalibrated.
Source: 567 IAC 83.5(4); DNR Certification Manual, Chapter 3, Sections 7.2.3 and 7.2.4
The DNR publishes its certification manual by program: water supply, underground storage tanks, wastewater and sewage sludge, and solid waste and contaminated sites. Check the chapter that matches each program area on your certificate.
Self-check
Are your initial calibrations ready for an Iowa 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.
What changed
Chapter 83 was revised in 2025.
The DNR revised Chapter 83 as part of its Executive Order 10 review of administrative rules. The final rules were published in the Iowa Administrative Bulletin on May 14, 2025 and took effect June 18, 2025. The chapter carries a rescission date of June 18, 2030 under Iowa Code section 17A.7.
The current rule connects Iowa to the national program in two specific ways without making Iowa a NELAP state. PT samples must come from a NELAP accredited provider, and the DNR accepts third-party accreditation from a state NELAP accreditation authority when the lab supplies its most recent on-site assessment and approved corrective action report.
Calibration remains method driven. The rule requires labs to run and document calibration curves annually and to supply calibration curves, MDL studies and LOQs on request. For wastewater, the manual adds a daily verification check within plus or minus 20 percent of the standard curve, or the system must be recalibrated.
How WLTR helps
Calibration evidence ready for an Iowa DNR audit.
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 Iowa DNR auditor.
See how your own ICAL data looks when every analyte and model is laid out for review.
Questions
Iowa accreditation FAQs
Is Iowa a NELAP state?
No. The Iowa DNR is not on TNI’s list of NELAP accreditation bodies. It certifies labs under 567 IAC Chapter 83, although it accepts third-party accreditation from a state NELAP accreditation authority and requires PT samples from a NELAP accredited provider.
Who certifies drinking water labs in Iowa?
The Iowa Department of Natural Resources, under the same Chapter 83 that covers wastewater and land quality programs. The DNR contracts with the State Hygienic Laboratory at the University of Iowa for technical assistance and auditing services.
Can an out-of-state lab be certified in Iowa?
Yes. Reciprocal certification may be granted to out-of-state labs. The DNR accepts third-party accreditation from a state NELAP accreditation authority, and a lab that loses its primary certification also loses Iowa certification for the same program area and parameters.
How long does Iowa certification last?
No more than two years from issuance, with renewal applications due at least 60 days before expiration. Labs must also pass PT for each analyte by each method every 12 months and consent to a site audit at least every two years.
Does Iowa have its own initial calibration rule?
567 IAC 83.5(4) requires labs to run and document calibration curves annually, and the DNR certification manual says calibration must follow the method. The manual’s wastewater chapter adds that daily curve checks should fall within plus or minus 20 percent or the system must be recalibrated.
Sources
Primary sources for this page.
- Iowa DNR, Environmental Laboratory Certification Program (opens in a new tab)
- Iowa DNR, certification and licensing programs (opens in a new tab)
- 567 IAC Chapter 83, Laboratory Certification (DNR copy) (opens in a new tab)
- 567 IAC 83.3, certification and reciprocity (Cornell LII copy) (opens in a new tab)
- 567 IAC 83.5, laboratory recertification (Cornell LII copy) (opens in a new tab)
- Iowa DNR, water quality rulemaking (opens in a new tab)
- DNR Certification Manual, Chapter 3, Wastewater and Sewage Sludge (opens in a new tab)
- TNI, NELAP recognized accreditation bodies (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 Iowa Department of Natural Resources. Spot something out of date? Tell us at admin@wltr.tech.
Before your next assessment
See your Iowa ICALs the way an auditor 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.