Maryland MDE
Maryland drinking water lab certification, MDE and COMAR 26.08.05.
Who certifies your lab in Maryland, which federal manual the rule adopts, how out-of-state labs qualify, and what auditors look for in your initial calibrations.
At a glance
How environmental lab certification works in Maryland.
Maryland is not a NELAP state. The Maryland Department of the Environment certifies labs that analyze drinking water compliance samples under its own statute and rule, which adopt the EPA drinking water certification manual.
Drinking water lab certification
- Program
- Laboratory Certification Program (LCP), Maryland Department of the Environment, which describes itself as the accreditation body for all certified drinking water laboratories in Maryland
- Legal basis
- Environment Article, Title 9, Subtitle 10 (Water Quality Laboratories), Annotated Code of Maryland; regulations in COMAR 26.08.05, Certification of State Water Quality Laboratories
- Standard adopted
- COMAR 26.08.05.02 incorporates the EPA Manual for the Certification of Laboratories Analyzing Drinking Water (EPA 815-R-05-004, January 2005) and its Supplement 1, along with parts of 40 CFR 141. The LCP page also lists Supplement 2.
- Who needs it
- Labs, in-state and out-of-state, that analyze compliance samples for Maryland public water systems. Certification covers specific parameters and test methods, and a lab must analyze at least one drinking water compliance sample per year to be eligible.
- Out-of-state labs
- May be certified if certified by U.S. EPA, TNI, or their home state under criteria at least as stringent as COMAR 26.08.05, with proof of that certification and acceptable PT results for each certified parameter and method (26.08.05.15)
- NELAP status
- Not a NELAP accreditation body, as of October 2026. COMAR 26.08.05.10 does require PT through a program administered under NELAP or a TNI approved accredited PT provider.
- Department of Health
- The Laboratories Administration of the Maryland Department of Health is the state public health laboratory. It tests samples, including from MDE, and its own drinking water certification has come from U.S. EPA Region III. MDE certifies other labs.
The accreditation cycle
From application to renewal.
The steps below summarize the statute and COMAR 26.08.05 for drinking water labs. Your certificate and MDE correspondence govern the specifics for your lab.
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Apply by parameter and method
The certificate lists the parameters and test methods the lab is certified for. New labs must pass performance testing for each parameter and have approved standard operating and quality assurance procedures.
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On-site evaluation
An in-state lab may not analyze regulated drinking water contaminants until MDE has conducted an on-site evaluation, and evaluations may be announced or unannounced. The statute requires each lab to be inspected at least triennially.
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Proficiency testing
Acceptable PT results for each method and parameter, from a program administered under NELAP or a TNI approved accredited provider, forwarded by the provider directly to MDE within 30 days of receipt. Without valid PT, certification is downgraded to provisional.
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Annual renewal
Certification is renewable annually. Labs apply at least 90 days before the expiration date, and a lab with an expired certification may not analyze drinking water compliance samples.
Initial calibration
What auditors check in your initial calibrations.
Maryland’s rule sets quality assurance requirements in COMAR 26.08.05.10 and adopts the EPA drinking water certification manual. The detailed calibration criteria come from the EPA drinking water methods your lab is certified for.
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 and QC written into the QA program
COMAR 26.08.05.10 requires regular operational checks and calibrations to assure proper operation and standardization of equipment, routine testing of standard reference samples, and quality control records kept on file for 5 years. Results may not be reported when quality control samples fall outside acceptable limits.
Source: COMAR 26.08.05.10, EPA Manual for the Certification of Laboratories Analyzing Drinking Water, 5th edition
COMAR 26.08.05.10 also requires the laboratory supervisor to certify that each test or analysis is accurate and valid. A calibration record that shows how each curve was accepted supports that signature.
Self-check
Are your initial calibrations ready for a Maryland 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.
Maryland specifics
A drinking water program, renewed every year.
Maryland’s certification law is written around drinking water. Environment Article, Title 9, Subtitle 10 defines a water quality laboratory as one that examines a public drinking water system, and MDE’s Laboratory Certification Program describes itself as the accreditation body for certified drinking water labs. Its program pages do not describe a separate wastewater laboratory certification.
The cycle is short. Certificates are renewable annually, the statute requires an inspection at least triennially, and certification is granted by parameter and test method. An out-of-state lab can be certified on the strength of EPA, TNI or home state certification, but only where those criteria are at least as stringent as COMAR 26.08.05 and the lab submits acceptable PT results.
The incorporated manual is the 2005 fifth edition with Supplement 1. The LCP homepage was last revised May 13, 2026 and now includes a section on the PFAS rule: PFAS monitoring results must be reported to MDE electronically through the Compliance Monitoring Data Portal (CMDP). MDE’s list of water regulations in development, as of September 8, 2026, shows no pending change to COMAR 26.08.05.
How WLTR helps
Calibration evidence ready for a Maryland on-site 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 MDE evaluator.
See how your own ICAL data looks when every analyte and model is laid out for review.
Questions
Maryland accreditation FAQs
Is Maryland a NELAP state?
No. The Maryland Department of the Environment is not a NELAP accreditation body, as of October 2026. Its rule does require proficiency testing through a program administered under NELAP or a TNI approved accredited provider.
Who certifies drinking water labs in Maryland?
The Laboratory Certification Program of the Maryland Department of the Environment, under Environment Article, Title 9, Subtitle 10 and COMAR 26.08.05. The Maryland Department of Health’s Laboratories Administration tests samples but does not run the certification program.
Does Maryland certify wastewater labs?
The certification statute and COMAR 26.08.05 are written for drinking water compliance testing, and MDE’s Laboratory Certification Program pages cover drinking water labs only. They do not describe a separate state wastewater lab certification.
Can an out-of-state lab analyze Maryland drinking water samples?
Yes, if it is certified by MDE. Under COMAR 26.08.05.15 an out-of-state lab may be certified based on U.S. EPA, TNI or home state certification with criteria at least as stringent as Maryland’s, plus proof of that certification and acceptable PT results. Renewal is required annually.
Does Maryland have its own initial calibration rule?
No separate calibration rule. COMAR 26.08.05.10 requires regular operational checks and calibrations, routine testing of standard reference samples and 5 years of QC records, and the detailed criteria come from the EPA methods the lab is certified for.
Sources
Primary sources for this page.
- MDE, Laboratory Certification Program (opens in a new tab)
- MDE, Environment Article Title 9, Subtitle 10, Water Quality Laboratories (opens in a new tab)
- COMAR 26.08.05, Certification of State Water Quality Laboratories (opens in a new tab)
- COMAR 26.08.05.10, Laboratory Quality Assurance Program (opens in a new tab)
- COMAR 26.08.05.15, out-of-state water quality laboratories (opens in a new tab)
- Maryland OneStop, drinking water laboratory certification (opens in a new tab)
- Maryland Department of Health, Laboratories Administration (opens in a new tab)
- TNI, NELAP 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 Maryland Department of the Environment. Spot something out of date? Tell us at admin@wltr.tech.
Before your next assessment
See your Maryland 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
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