Colorado CDPHE
Colorado environmental lab certification, CDPHE and the EPA drinking water manual.
Who certifies your lab in Colorado, which standard the rule adopts, how out-of-state labs qualify, where wastewater stands, and what auditors look for in your initial calibrations.
At a glance
How environmental lab certification works in Colorado.
Colorado is not a NELAP state. Its certification rule covers labs testing drinking water and adopts the EPA drinking water certification manual rather than the TNI standard.
Drinking water lab certification
- Program
- Laboratory Certification Program, Laboratory Services Division of the Colorado Department of Public Health and Environment (CDPHE)
- Legal basis
- 5 CCR 1005-1, Environmental Laboratory Certification, effective December 15, 2014. The rule cites C.R.S. 25-1.5-101(e), which delegates laboratory approval and certification to the department.
- Standard adopted
- EPA Manual for the Certification of Laboratories Analyzing Drinking Water, Fifth Edition (EPA 815-R-05-004, January 2005), with supplements 1 and 2. Later amendments or editions are not included (5 CCR 1005-1.3.1).
- Who needs it
- Labs seeking certification to test samples under the Colorado Primary Drinking Water Regulations and the federal Safe Drinking Water Act. Chemistry, microbiology and radiochemistry are certified independently.
- Out-of-state labs
- Reciprocity certification is available based on another state agency accrediting or certifying authority. The lab must keep that certification current and report status changes within 30 calendar days (5 CCR 1005-1.3.7.2).
- Wastewater
- 5 CCR 1005-1 addresses drinking water testing only. For discharge permits, Regulation 61 requires permittee sampling to follow the test procedures of 40 CFR Part 136 (5 CCR 1002-61.8(4)(i)).
- NELAP status
- Not a NELAP accreditation body as of October 2026. Colorado does not appear on TNI’s list of NELAP-recognized accreditation bodies.
The accreditation cycle
From application to renewal.
The steps below summarize 5 CCR 1005-1 for drinking water labs. Your certificate and CDPHE correspondence govern the specifics for your lab.
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Primary or reciprocity
Request primary certification, which involves a CDPHE onsite inspection, or reciprocity certification based on another state’s certification (5 CCR 1005-1.3.7).
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Proficiency testing
Certification depends on successful participation in proficiency test programs (5 CCR 1005-1.3.6).
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Inspections
CDPHE states that it inspects labs on site every two years. Routine inspections are announced at least five days ahead, and complaint inspections may be unannounced (5 CCR 1005-1.3.7.1).
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Annual renewal
Certifications are issued annually, and reapplications are due at least 90 days before the existing certification expires (5 CCR 1005-1.3.4 and 1.3.6).
Initial calibration
What auditors check in your initial calibrations.
Colorado has no separate calibration rule. Its certification rule adopts EPA’s drinking water certification manual, so the calibration requirements come from that manual and from the drinking water methods you are 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.
The 2005 EPA manual, as Colorado adopted it
5 CCR 1005-1 adopts the Fifth Edition of EPA’s Manual for the Certification of Laboratories Analyzing Drinking Water (2005) with supplements 1 and 2, and states that later editions are not included. Colorado sets no calibration rule of its own, so auditors look to that manual and the approved drinking water methods.
Source: 5 CCR 1005-1.3.1, EPA 815-R-05-004 and supplements 1 and 2
Routine CDPHE inspections are announced at least five days in advance under 5 CCR 1005-1.3.7.1. A complete, consistent calibration record is the part of that visit you can prepare before the notice arrives.
Self-check
Are your initial calibrations ready for a Colorado 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.
Colorado specifics
A drinking water rule built on the 2005 EPA manual.
Colorado’s certification rule is narrow by design. 5 CCR 1005-1 sets minimum standards for labs testing samples under the Colorado Primary Drinking Water Regulations and the Safe Drinking Water Act, and it states that it affords interstate recognition by adopting the SDWA standards in their entirety. It does not address wastewater; Regulation 61 instead requires discharge permittees to sample using 40 CFR Part 136 test procedures.
The rule fixes a specific edition. It adopts the Fifth Edition of the EPA drinking water certification manual from 2005, with supplements 1 and 2, and excludes later amendments or editions. The rule has been in effect since December 15, 2014, and the Cornell LII copy lists no later amendments as of October 2026.
Certification is also renewed every year. Certificates are issued annually and depend on successful proficiency testing, reapplication is due at least 90 days before expiration, and CDPHE states that it inspects labs on site every two years. A calibration record kept complete between inspections is easier to defend than one assembled the week before.
How WLTR helps
Calibration evidence ready for a Colorado 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 CDPHE auditor.
See how your own ICAL data looks when every analyte and model is laid out for review.
Questions
Colorado accreditation FAQs
Is Colorado a NELAP state?
No. Colorado is not on TNI’s list of NELAP-recognized accreditation bodies as of October 2026. CDPHE certifies drinking water labs under its own rule, 5 CCR 1005-1.
Who certifies drinking water labs in Colorado?
The Laboratory Certification Program in CDPHE’s Laboratory Services Division, under 5 CCR 1005-1. Chemistry, microbiology and radiochemistry are certified independently.
Does Colorado certify wastewater labs?
Colorado’s certification rule, 5 CCR 1005-1, addresses drinking water testing only. For discharge permits, Regulation 61 requires permittee sampling to follow the test procedures of 40 CFR Part 136.
Can an out-of-state lab be certified in Colorado?
Yes, through reciprocity certification based on another state agency accrediting or certifying authority. The lab must keep that certification current and report any change in status to CDPHE within 30 calendar days.
How long does Colorado certification last?
Certifications are issued annually based on complete application documents and successful participation in proficiency test programs. Reapplications are due at least 90 days before the existing certification expires.
Sources
Primary sources for this page.
- TNI, NELAP-recognized accreditation bodies (opens in a new tab)
- 5 CCR 1005-1, official text (Colorado Secretary of State) (opens in a new tab)
- 5 CCR 1005-1.1, scope (Cornell LII copy) (opens in a new tab)
- 5 CCR 1005-1.3, certification requirements (Cornell LII copy) (opens in a new tab)
- Division 1005, Laboratory Services Division rules (Cornell LII copy) (opens in a new tab)
- 5 CCR 1002-61.8, discharge permit conditions (Cornell LII copy) (opens in a new tab)
- CDPHE, drinking water lab certification (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 Colorado Department of Public Health and Environment. Spot something out of date? Tell us at admin@wltr.tech.
Before your next assessment
See your Colorado 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.