Connecticut DPH ELCP
Connecticut environmental lab certification, one department for every matrix.
Who certifies your lab in Connecticut, which tests are excluded, how out-of-state labs are approved, and what the regulations say about calibration.
At a glance
How environmental lab certification works in Connecticut.
Connecticut is not a NELAP state. The Department of Public Health certifies environmental labs under its own statute and regulations, covering drinking water, wastewater, solid waste and soil, tissues and asbestos in a single program.
State program (non-NELAP)
- Program
- Environmental Laboratory Certification Program (ELCP), Connecticut Department of Public Health
- Legal basis
- Connecticut General Statutes section 19a-29a; Regulations of Connecticut State Agencies sections 19a-36-A25 through 19a-36-A33 (registration and approval) and 19a-36-A57 through 19a-36-A63 (environmental laboratories)
- Who needs it
- Labs located in or doing business in Connecticut, private, municipal and industrial non-commercial, that test for analytes on the DPH list. Certification is required before testing begins (CGS 19a-29a, as amended by Public Act 26-142).
- Areas of approval
- Chemical and microbiological examination of drinking water, non-potable water and wastewater, solid waste and soil, animal and plant tissues, and asbestos (air fibers, bulk materials and water)
- Exclusions
- CGS 19a-29a excludes a publicly-owned treatment works that performs only physical, residue, microbiological and BOD tests for its own facility to meet DEEP permits, and a pollution abatement facility running pH, turbidity, conductivity, salinity, ORP and residual chlorine tests for its own facility.
- Out-of-state labs
- Must be approved by DPH to test samples that originate in Connecticut, based on certification by their primary accrediting authority (RCSA 19a-36-A33(c)).
- NELAP status
- Not a NELAP accreditation body. RCSA 19a-36-A33(c) names NELAP as an example of a nationally recognized program DPH may rely on for out-of-state approval in some cases.
The accreditation cycle
From application to renewal.
The steps below summarize the DPH regulations and ELCP guidance. Your certificate and ELCP correspondence govern the specifics for your lab.
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Certify before testing
Apply on DPH forms and obtain certification before any regulated examination begins (CGS 19a-29a as amended in 2026; RCSA 19a-36-A25 and A27).
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Department review
Approval is granted only after a department determination under RCSA 19a-36-A29, and DPH representatives must be granted reasonable access to laboratory quarters and records (A31).
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Annual proficiency testing
ELCP requires in-state labs to run PT samples annually: one for each drinking water method, and one matrix-specific sample per listed analyte for non-potable water, wastewater and solid waste or soil (Circular Letter 2021-15).
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Biennial renewal
Renewal is due biennially, within the twenty-fourth month of the current registration under CGS 19a-29a(f), and certificates expire at the end of each registration period (RCSA 19a-36-A33).
Initial calibration
What auditors check in your initial calibrations.
Connecticut’s environmental laboratory regulations do not set numeric calibration criteria of their own. They require written methods at the bench, including calibration procedures, and the acceptance criteria come from the department-approved 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 procedures at the bench
RCSA 19a-36-A59 requires current written methods in the immediate bench area, including information on the preparation and storage of reagents, standards and calibration procedures. An auditor can compare what the analyst did with what the bench copy says.
Source: RCSA 19a-36-A59
Labs producing data for Connecticut DEEP remediation work should also check DEEP’s Reasonable Confidence Protocols, which set QA and QC expectations method by method. Check the current versions on DEEP’s quality assurance and quality control page.
Self-check
Are your initial calibrations ready for a Connecticut 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.
Connecticut specifics
One department certifies every matrix.
The Department of Public Health’s ELCP certifies environmental labs for drinking water, wastewater, sewage, solid waste and soils, for microbiologicals, inorganics, organics and radiochemicals. The same program also covers animal and plant tissues and asbestos.
Not every wastewater test needs a certified lab. CGS 19a-29a excludes a publicly-owned treatment works that performs only physical, residue, microbiological and BOD tests for its own facility to meet DEEP permits, and a similar exclusion covers pollution abatement facilities running a short list of field-type tests. Out-of-state labs must be approved by DPH before testing Connecticut samples.
Remediation data has its own guidance. Most of DEEP’s Reasonable Confidence Protocols carry a May 2024 date, and a PFAS Method 1633 protocol took effect July 1, 2026. Public Act 26-142 amended CGS 19a-29a effective October 1, 2026, while the DPH lab regulations still date from 1995.
How WLTR helps
Calibration evidence ready for a Connecticut 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 state auditor.
See how your own ICAL data looks when every analyte and model is laid out for review.
Questions
Connecticut accreditation FAQs
Is Connecticut a NELAP state?
No. The Connecticut Department of Public Health is not a NELAP accreditation body. It certifies environmental labs under CGS 19a-29a and its own regulations.
Who certifies environmental labs in Connecticut?
The Environmental Laboratory Certification Program of the Connecticut Department of Public Health, for drinking water, non-potable water and wastewater, solid waste and soil, animal and plant tissues, and asbestos.
Does a wastewater treatment plant lab need certification?
Not always. CGS 19a-29a excludes a publicly-owned treatment works that performs only physical, residue, microbiological and BOD tests for its own facility to comply with DEEP permits. Other testing for listed analytes requires a certified lab.
Can an out-of-state lab test Connecticut samples?
Yes, once DPH approves it. RCSA 19a-36-A33(c) bases approval on certification by the lab’s primary accrediting authority, and the renewal form asks for that authority’s list of certified analytes.
How often must a Connecticut lab renew and run PT?
Certification is renewed biennially, within the twenty-fourth month of the current registration (CGS 19a-29a(f)). ELCP requires in-state labs to run proficiency test samples annually for the drinking water, wastewater and solid waste or soil matrices.
Sources
Primary sources for this page.
- CT DPH, Environmental Laboratory Certification Program (opens in a new tab)
- CT DPH, ELCP laws and regulations (opens in a new tab)
- RCSA 19a-36-A57 through A63, environmental laboratories (opens in a new tab)
- RCSA section 19a-36, including A25 through A33 (Secretary of the State) (opens in a new tab)
- CGS 19a-29a, environmental laboratories (Justia, 2025 text before Public Act 26-142) (opens in a new tab)
- CT DPH Circular Letter 2021-15, proficiency tests (opens in a new tab)
- CT DEEP, quality assurance and quality control (RCPs) (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 Connecticut Department of Public Health. Spot something out of date? Tell us at admin@wltr.tech.
Before your next assessment
See your Connecticut 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.