Wyoming and EPA Region 8
Wyoming drinking water lab certification, EPA Region 8 and federal methods.
Why EPA rather than the state certifies drinking water labs in Wyoming, how out-of-state labs qualify, which federal rules set the methods, and what auditors look for in your initial calibrations.
At a glance
How drinking water lab certification works in Wyoming.
Wyoming has not applied for primacy over its public water supply program, so EPA Region 8 directly implements the Safe Drinking Water Act in the state, including laboratory certification. Status as of October 2026.
Drinking water lab certification
- Drinking water certification
- EPA Region 8 Laboratory personnel perform on-site evaluations and certify Wyoming laboratories for particular drinking water analytes and analytical methods.
- Why EPA
- EPA states that Region 8 directly implements the Safe Drinking Water Act in Wyoming and lists laboratory certification among Region 8’s responsibilities. Wyoming DEQ likewise states that EPA Region 8 runs the Safe Drinking Water Act laboratory certification program in Wyoming.
- Legal basis
- 40 CFR 141.28: compliance samples may be considered only if analyzed by a laboratory certified by EPA or the State, except field measurements such as pH, temperature, turbidity and disinfectant residual.
- Surface water quality data
- Wyoming DEQ’s surface water quality rules (Chapter 1, Section 10) call for test procedures under Title 40, Code of Federal Regulations, Part 136.
- Out-of-state labs
- EPA Region 8 accepts reciprocal certification for laboratories certified in other states.
- Water system duty
- EPA states it is the responsibility of the water system to ensure that the laboratory certification is current for the analyte of interest.
- NELAP status
- No Wyoming agency appears on TNI’s list of NELAP recognized accreditation bodies.
The accreditation cycle
How EPA Region 8 certification works.
The steps below summarize EPA Region 8’s published pages and lab list for Wyoming. Your certification letter and Region 8 correspondence govern the specifics for your lab.
-
Certify by analyte and method
Region 8 certifies Wyoming labs for particular drinking water analytes and analytical methods, so certification covers specific analyte and method pairs, not the lab as a whole.
-
On-site evaluation
EPA Region 8 Laboratory personnel perform on-site evaluations of Wyoming laboratories.
-
Reciprocity for out-of-state labs
Region 8 accepts reciprocal certification for laboratories certified in other states.
-
Published lab list
Region 8 publishes a list of certified drinking water laboratories in Wyoming, most recently current as of February 2026, and water systems are responsible for confirming certification is current.
Initial calibration
What auditors check in your initial calibrations.
Wyoming sets no calibration rule of its own for drinking water labs. Calibration expectations come from the federal methods your lab is certified for under 40 CFR 141 and, for surface water quality data, the 40 CFR 136 test procedures Wyoming’s rules adopt.
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.
Federal methods set the calibration bar
Wyoming adopts federal test procedures rather than writing its own calibration rule. For 40 CFR 136 work, 40 CFR 136.7 requires the method’s own QC, and lists calibration (initial and continuing) as an element where a method has none.
Source: Wyoming Water Quality Rules Ch. 1, Sec. 10; 40 CFR 136.7
Drinking water labs are certified method by method, so the calibration criteria in each approved method are the ones an EPA Region 8 evaluator will compare your records against.
Self-check
Are your initial calibrations ready for a Wyoming 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.
Wyoming specifics
In Wyoming, EPA certifies drinking water labs.
EPA describes Wyoming as the only state that has not applied for authority to run its own public water supply program. Region 8 therefore directly implements the Safe Drinking Water Act in Wyoming, and EPA lists laboratory certification among Region 8’s responsibilities. Wyoming DEQ points to the same arrangement for the Safe Drinking Water Act laboratory certification programs.
In practice, Region 8 Laboratory personnel perform on-site evaluations and certify labs for particular analytes and methods. Region 8 accepts reciprocal certification for labs certified in other states, and EPA places the duty to confirm a lab’s certification is current on the water system.
Region 8 updated its Wyoming certification page in February 2026 and published a certified laboratory list current as of February 2026. For surface water quality data, Wyoming’s rules point to the 40 CFR 136 test procedures, where 40 CFR 136.7 requires each method’s own QC, including calibration.
How WLTR helps
Calibration evidence ready for an EPA Region 8 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 an EPA Region 8 evaluator.
See how your own ICAL data looks when every analyte and model is laid out for review.
Questions
Wyoming accreditation FAQs
Is Wyoming a NELAP state?
No. No Wyoming agency appears on TNI’s list of NELAP recognized accreditation bodies.
Who certifies drinking water labs in Wyoming?
EPA Region 8. Because Wyoming has not sought primacy, Region 8 directly implements the Safe Drinking Water Act in the state, and Region 8 Laboratory personnel perform on-site evaluations and certify labs for particular analytes and methods.
Can an out-of-state lab analyze Wyoming drinking water samples?
EPA Region 8 states that it accepts reciprocal certification for laboratories certified in other states. The water system is responsible for ensuring the lab’s certification is current.
Which methods apply to Wyoming surface water quality data?
Wyoming DEQ’s surface water quality rules (Chapter 1, Section 10) call for test procedures under 40 CFR Part 136.
Does Wyoming have its own initial calibration rule?
Not one we found. Calibration requirements come from the approved federal methods, and for 40 CFR 136 work, 40 CFR 136.7 adds initial and continuing calibration where a method lacks its own QC.
Sources
Primary sources for this page.
- EPA, Certified Drinking Water Laboratories for Systems in Wyoming and on Tribal Lands (opens in a new tab)
- EPA Region 8, Certified Drinking Water Laboratories in Wyoming (February 2026 list) (opens in a new tab)
- EPA, Basic Information about Wyoming and Tribal Drinking Water Programs (opens in a new tab)
- Wyoming DEQ, Water and Wastewater (opens in a new tab)
- 40 CFR 141.28, certified laboratories (eCFR) (opens in a new tab)
- 40 CFR 136.7, quality assurance and quality control (eCFR) (opens in a new tab)
- Wyoming Water Quality Rules Ch. 1, Sec. 10, testing procedures (Justia copy) (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 U.S. Environmental Protection Agency, Region 8. Spot something out of date? Tell us at admin@wltr.tech.
Before your next assessment
See your Wyoming ICALs the way an 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.