Maine MLAP
Maine environmental lab accreditation, MLAP and Chapter 263.
Who accredits your lab in Maine, which rule you are inspected against, how out-of-state labs qualify, and the calibration requirements Maine wrote into its own rule.
At a glance
How environmental lab accreditation works in Maine.
Maine is not a NELAP state. A single program within the Maine CDC accredits labs that produce compliance data for both the Department of Health and Human Services and the Department of Environmental Protection, under a rule the two departments adopted jointly.
State program (non-NELAP)
- Program
- Maine Laboratory Accreditation Program (MLAP), within the Maine Center for Disease Control and Prevention, Department of Health and Human Services. Maine CDC accredits labs that perform compliance testing of public drinking water or wastewater.
- Legal basis
- 22 MRS chapter 157-A, section 567; Maine Comprehensive and Limited Environmental Laboratory Accreditation Rule, 10-144 CMR and 06-096 CMR Chapter 263, adopted jointly by DHHS and DEP and last amended effective March 15, 2023
- Who needs it
- All laboratories, including industrial, commercial, academic and governmental, that analyze samples under the Safe Drinking Water Act, the Clean Water Act, the Resource Conservation and Recovery Act, and the Leaking Underground Storage Tanks program for DHHS or DEP (Ch. 263, section 1.A)
- Wastewater facility exception
- Labs at wastewater discharge facilities licensed under 38 MRS section 413 may analyze their discharges for listed parameters, including BOD, pH, total suspended solids and E. coli, without accreditation. The exception covers their own permit samples, pretreatment samples, and other plants’ samples for up to 60 days of analysis per year.
- Matrices and methods
- Drinking water, non-potable water, air, and solid and chemical materials, including tissues and septage. Wastewater methods are those in 40 CFR Part 136, drinking water methods those in 40 CFR Part 141, and RCRA methods include SW-846.
- Out-of-state labs
- May apply only for programs, matrices, methods or analytes in which they hold primary certification or accreditation by another approving body, and must submit their most recent on-site assessment report. MLAP treats a program as equivalent only if its criteria are at least as stringent as Chapter 263.
- NELAP status
- Not a NELAP accreditation body, as of October 2026. Chapter 263 sets its own quality system requirements in Section 8.
The accreditation cycle
From application to renewal.
MLAP accredits labs by the tests they offer. The steps below summarize Chapter 263; your certificate, scope of accreditation and MLAP correspondence govern the specifics for your lab.
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Apply by test
Labs are accredited by the tests they offer. Initial applicants must successfully complete at least one proficiency test sample, unless one is not available, analyzed within six months of the date the application is received.
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Proficiency testing
Accredited labs must complete proficiency testing studies for each field of testing each calendar year (Ch. 263, section 10.C).
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On-site inspection
The accreditation officer conducts a comprehensive on-site inspection of each Maine lab before accreditation, and an on-site inspection of each Maine accredited lab may be completed every two years (section 5.A).
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Renewal
Accreditation is valid for one or two years from the date of base accreditation or renewal. Renewal applications must be received no later than 60 days before expiration, and results may not be reported as accredited after accreditation expires.
Initial calibration
What auditors check in your initial calibrations.
Because Maine writes its own rule, the calibration expectations sit in Section 8(O) of Chapter 263, alongside the approved methods in 40 CFR Parts 136 and 141, rather than in a TNI module.
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.
Second source and written acceptance criteria
Chapter 263 requires records sufficient to reconstruct the instrument calibration, sample results quantitated from the most recent calibration, and verification of every instrument calibration with a second-source standard when available. The lab must establish acceptance criteria, such as correlation coefficient or relative standard deviation.
Source: 10-144 CMR Ch. 263, section 8(O)(3)
Section 8(O)(4) adds calibration verification. When the calibration is not performed on the day of analysis it must be verified, and if the approved method does not describe verification, it is repeated at the beginning of each batch, after every tenth sample excluding QC samples, and at the end of each batch.
Self-check
Are your initial calibrations ready for a Maine 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.
Maine specifics
One program and one rule for drinking water and wastewater.
Many states split drinking water and wastewater lab certification between two agencies. Maine does not. MLAP, within the Maine CDC, accredits labs for drinking water, non-potable water, air, and solid and chemical materials under Chapter 263, a rule DHHS and DEP adopted jointly for labs producing compliance data for either department.
That rule carries its own calibration language. Section 8(O) requires second-source verification when a second source is available, written acceptance criteria such as correlation coefficient or relative standard deviation, and records that allow the calibration to be reconstructed. Results outside the calibrated range may be reported only where the permit, program or rule allows it, with qualifiers.
The most recent amendment to Chapter 263 took effect March 15, 2023. Among other changes, it revised the fee schedule and updated federal regulation citations to the 2022 annual edition. As of October 2026, the Maine CDC rules page lists no newer Chapter 263 rulemaking.
How WLTR helps
Calibration evidence ready for a Maine inspection.
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 Maine CDC auditor.
See how your own ICAL data looks when every analyte and model is laid out for review.
Questions
Maine accreditation FAQs
Is Maine a NELAP state?
No. Maine is not listed by TNI as a NELAP accreditation body, as of October 2026. MLAP accredits labs under Maine’s own rule, 10-144 CMR and 06-096 CMR Chapter 263.
Who accredits drinking water and wastewater labs in Maine?
The Maine Laboratory Accreditation Program within the Maine CDC, Department of Health and Human Services. One program covers labs analyzing samples under the Safe Drinking Water Act, the Clean Water Act, RCRA and the LUST program.
Do wastewater treatment plant labs need accreditation?
Not for every test. Labs at licensed wastewater discharge facilities may analyze listed parameters, such as BOD, pH, total suspended solids and E. coli, without accreditation, for their own permit samples, pretreatment samples, and other plants’ samples for up to 60 days of analysis per year.
Can an out-of-state lab be accredited in Maine?
Yes, for programs, matrices, methods or analytes in which it holds primary certification or accreditation from another approving body. The lab submits its most recent on-site assessment report, and MLAP must find the primary program at least as stringent as Chapter 263.
Does Maine have its own initial calibration rule?
Yes. Chapter 263, section 8(O)(3) requires records sufficient to reconstruct the calibration, second-source verification when available, and established acceptance criteria such as correlation coefficient or relative standard deviation.
Sources
Primary sources for this page.
- Maine CDC, laboratory accreditation (opens in a new tab)
- 10-144 CMR Ch. 263, laboratory accreditation rule (PDF) (opens in a new tab)
- Maine DHHS, Chapter 263 rulemaking, effective March 15, 2023 (opens in a new tab)
- 22 MRS section 567, certification or accreditation program (opens in a new tab)
- Ch. 263, section 1, administration (Justia, secondary copy) (opens in a new tab)
- Ch. 263, section 8, quality systems (Justia, secondary 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 Maine Center for Disease Control and Prevention. Spot something out of date? Tell us at admin@wltr.tech.
Before your next assessment
See your Maine 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.