How to Verify Water Quality Claims: A Step-by-Step Guide

Written by: Scott Steveson, Specialist, Wellness Quality Institute

What You Will Learn About Verifying Water Claims

• National Water Quality Month brings a surge of water claims on packaging and websites, yet the gap between supported and unsupported claims often stays hidden from compliance teams and consumers.

• A repeatable verification checklist connects common claim types to public records and documentation standards, so brands and consumers can see what a dataset truly supports.

• Plastic and microplastic reduction claims need extra scrutiny because no federal standard for microplastics in drinking water exists and laboratory capability varies widely.

• The six-step verification playbook offers a neutral process for evaluating claims, and independent review is the most important and most frequently skipped step.

• The Wellness Quality Institute offers Plastic-Free Pathway Verification to help brands substantiate plastic or microplastic reduction claims with existing laboratory data, and to turn that data into a defensible claim.

Core Terms You Need Before Verifying Claims

A shared vocabulary keeps everyone aligned before any verification process begins. These terms appear throughout the checklist and shape what a claim can honestly say.

Verification means an independent review of existing evidence against defined criteria. It is not the same as testing. Verification examines data that already exists instead of generating new data.

Validation refers to confirming that a method or process does what it is supposed to do under defined conditions. A laboratory method must be validated before anyone can rely on its results.

Scope defines the boundaries of any claim or review. Scope covers which product, which production period, which contaminants, and which particle sizes are included. A claim is only as strong as the scope of the evidence behind it.

Detection limit, also called the method detection limit or MDL, is the lowest concentration or particle count a given analytical method can reliably identify. A result of “none detected” means none found above this floor, not that none are present. FTIR and Raman spectroscopy, the dominant methods for microplastic identification in drinking water, have practical lower size limits of roughly 50 µm and 20 µm respectively. Particles smaller than those thresholds sit completely outside the method’s reach.

Chain of custody is the documented record showing who collected a sample, how it was handled, and how it moved from collection through analysis. Without this record, no one can confirm that a laboratory result reflects the product rather than contamination introduced during handling.

Accreditation is independent recognition that a laboratory meets defined competency standards. ISO/IEC 17025:2017 is the general international standard for laboratory competence, and the Environmental Laboratory Accreditation Program is the state-level accreditation for laboratories applying a state’s published microplastics methods.

One structural gap shapes every step that follows. No validated, standardized EPA analytical method for microplastics in drinking water currently exists. That absence means plastic and microplastic reduction claims have no federal benchmark to measure against, so the documentation standards in Steps 3 and 5 below carry even more weight.

How Different Claim Types Connect to Evidence

Different claim types rely on different evidence sources, and each source has clear limits. The table below maps four common claim categories to their main verification sources and the boundaries of what each source can support.

Claim Type	Primary Verification Source	Scope Limitation
Utility water quality statement (e.g., “meets all federal standards”)	Consumer Confidence Report (CCR) and EPA SDWIS / ECHO Dashboard	Covers regulated contaminants only, and does not include microplastics, which have no federal MCL
Brand marketing copy (e.g., “sourced from pristine water”)	CCR for source water summary, independent laboratory data for specific contaminant claims	Source water quality at intake does not equal finished-product quality, because packaging and processing create separate contamination routes
Filter or treatment device performance (e.g., “reduces lead by 99%”)	NSF International certification registry or WQA Gold Seal database	Certification is contaminant-specific and model-specific, so a filter certified for chlorine reduction is not automatically certified for lead or microplastics
Plastic or microplastic reduction claim (e.g., “no microplastics detected”)	Independent laboratory data reviewed against a defined standard, plus independent third-party review	“None detected” is bounded by the method’s detection floor, the polymer panel tested, and the production lot sampled, not a guarantee of absence

The fourth row is the one most likely to be misread. A laboratory report stating “no microplastics detected” is a bounded finding, not an absolute one. Credible microplastic documentation must include the method detection limit, procedural blank results, filtration volume processed, polymer identification technique, and the explicit rule used to classify results as non-quantifiable. These details rarely appear on a product label or in a press release.

Six-Step Playbook for Verifying Water Quality Claims

The six steps below create a repeatable process for evaluating water quality claims. Each step ends with a decision checkpoint that clarifies whether the evidence supports the claim.

Step 1: Locate and Read the Consumer Confidence Report

Community water systems must publish an annual CCR. EPA’s Find Your Local CCR tool lets users search by utility name or location. Within the report, start by checking detected contaminant levels against Maximum Contaminant Levels (MCLs, the legally enforceable limits) and MCLGs (Maximum Contaminant Level Goals, the health-based targets, which are often lower). This comparison shows how much safety margin exists beyond legal compliance.

Next, review the source water type and any source water assessment summary to understand what contaminants the system is designed to address. Then check for any violations disclosed, including health-based violations that indicate exceedances and monitoring or reporting violations that suggest gaps in oversight. Finally, read the plain-language summary section, which becomes a required front-page element under the revised CCR Rule effective January 1, 2027.

Decision checkpoint: Confirm whether the CCR covers the specific contaminants referenced in the claim. If the claim involves microplastics, the CCR will not address it, so move to Step 3.

Step 2: Cross-Reference Federal Databases for Violations and Compliance

EPA’s Safe Drinking Water Information System (SDWIS) and the ECHO Drinking Water Dashboard provide national violation and compliance data reported by state primacy agencies. The EWG Tap Water Database aggregates utility testing data and compares detected levels against both legal limits and health guidelines.

Note that SDWIS data updates quarterly with a three-month lag and may not reflect all compliance monitoring. State primacy agency databases often carry more current or more detailed information. Record any discrepancy between what the CCR reports and what SDWIS or EWG shows for the same system and period.

Decision checkpoint: Check whether contaminant levels and violation records stay consistent across sources. Any discrepancy calls for direct contact with the utility or state primacy agency before using the data to support a claim.

Step 3: Evaluate Independent Laboratory Data for Plastic and Microplastic Claims

Claims that reference plastic, microplastic, or microplastic-free language sit outside CCR and SDWIS coverage, because no federal MCL for microplastics exists, as noted earlier. The claim must rest on independent laboratory data. That data should specify the analytical method used, such as µ-FTIR or Raman spectroscopy, and its validated size range.

The data should also list the polymer types screened, at minimum PE, PP, PET, PS, and PVC, the particle-size fractions reported, and the detection limit for each fraction. A result of “none detected” without these specifics cannot support a reduction claim.

If your laboratory data covers plastic or microplastic reduction, the Wellness Quality Institute’s Plastic-Free Pathway Verification can help you determine what claims that data actually supports.

Decision checkpoint: Confirm that the laboratory data covers the polymer types and particle-size range implied by the claim. If the method starts at 50 µm, the claim cannot address smaller particles. If the polymer panel excludes polypropylene, the polymer most commonly identified in a 2018 Frontiers in Chemistry study of 259 bottled water samples, the claim has a significant gap.

Step 4: Verify Filter and Treatment Device Certifications

Claims that a filter or treatment device reduces a specific contaminant should start with the NSF International certified products database or the WQA Gold Seal database. Search by exact manufacturer name and model number, not brand name alone.

NSF/ANSI certification is contaminant-specific, so a filter certified under NSF/ANSI 42 for chlorine taste and odor reduction carries no certification for lead, PFAS, or microplastics. Phrases such as “tested to NSF standards” or “tested in a certified lab” do not indicate actual certification and should not be treated as equivalent.

Decision checkpoint: Confirm that the registry listing shows certification for the specific contaminant named in the claim and for the exact model number being marketed. If not, the claim goes beyond what the certification supports.

Step 5: Assess Documentation Quality and Laboratory Controls

A laboratory report is only as reliable as the controls around it. Credible microplastic documentation requires procedural blank results, the method detection limit, filtration volume processed, and the polymer identification technique. A complete evidence packet for a plastic-reduction claim should also include chain-of-custody records from sample collection through analysis.

Procedural blanks should confirm that detected particles came from the sample rather than the laboratory environment. Spike recoveries should demonstrate the method’s ability to find what it is looking for. Reporting limits should appear by size fraction rather than as a single aggregate figure. The laboratory’s accreditation status should confirm ISO/IEC 17025 with the method and matrix explicitly in scope, or state-level accreditation for the applicable microplastics method.

Decision checkpoint: Check whether every element of the documentation is present and internally consistent. Missing chain-of-custody records, blanks that show contamination, or reporting limits that sit above the method floor are early warning signs that the dataset cannot support the claim.

Step 6: Obtain Independent Review of the Dataset

Independent review becomes necessary when a brand’s plastic or microplastic reduction claim language goes beyond what the dataset can demonstrate, or when a self-reported laboratory result must carry weight with retailers, procurement teams, or consumers. Self-reported data, however rigorous the testing, is often treated as marketing.

An independent review against published criteria produces a finding that neither the brand nor its laboratory can produce alone. That finding gives buyers and regulators a clearer basis for trust.

The Wellness Quality Institute, introduced here by its full name, offers Plastic-Free Pathway Verification (PFPV), governed by the standard WQI-CS-01, as the independent review option for US brands making plastic or microplastic reduction claims. WQI reviews a company’s existing independent laboratory dataset, testing methodology, product scope, and supporting controls against defined criteria focused on particle size and polymer type, aligned with a state water board’s drinking-water microplastics reference framework.

Every review produces one of two outcomes: Standard Met or Standard Not Met. A Standard Not Met outcome is private and can be resubmitted with updated information, so it carries no public downside risk.

Request an independent review of your laboratory dataset to understand its scope and limitations.

Decision checkpoint: Confirm whether an independent party has reviewed the claim language against published criteria. Without that review, the brand is asserting rather than substantiating, which matters increasingly to retailers, procurement teams, and litigators.

Recurring Documentation Problems and How to Fix Them

Several documentation problems appear again and again in plastic and microplastic reduction claims. Recognizing them early reduces the cost of correction.

Missing chain-of-custody records. Sampling often gets treated as a logistics task instead of a documentation task. The corrective action is to establish a written sampling protocol before collection begins and to complete chain-of-custody forms at each transfer point.

Reporting limits below the method floor. A laboratory may report a detection limit that the instrument cannot actually achieve for the matrix in question. No single analytical technique currently provides comprehensive microplastic characterization across all environmentally relevant particle-size classes and matrix types. The corrective action is to confirm, before commissioning testing, that the laboratory’s validated detection range for the specific matrix matches the particle-size range the claim will reference.

Scope creep. A result from one product, one production lot, and one analytical method gets stretched to cover a product line or a brand-wide claim. The corrective action is to define the claim scope in writing before the laboratory report appears in any marketing and to confirm that every public statement stays inside that scope.

Laboratory accreditation gaps. A laboratory may hold ISO/IEC 17025 accreditation without the specific microplastics method or the specific matrix, such as drinking water, bottled water, or a functional beverage, explicitly within its accredited scope. The corrective action is to request the laboratory’s scope of accreditation document and confirm that both the method and the matrix are listed before commissioning testing.

What Strong Evidence for Plastic Claims Looks Like

A complete, defensible evidence packet for a plastic or microplastic reduction claim has several clear characteristics.

• The laboratory report identifies the analytical method, instrument, validated size range, and polymer panel explicitly.

• Procedural blank results are reported and show no contamination above the method detection limit.

• Particle counts are reported by size fraction, not as a single aggregate figure.

• Chain-of-custody records are present and unbroken from sample collection through analysis.

• The laboratory’s accreditation status is confirmed and covers the method and matrix in scope.

• Claim language is bounded to the reviewed product, production period, tested size range, and polymer panel.

• For verified products, a public registry ID is available for independent confirmation of scope.

A quarterly documentation audit offers a practical monitoring approach for brands that maintain ongoing plastic-related claims. This audit reviews whether the evidence packet remains current, whether production has changed in ways that affect the tested scope, and whether the verification period remains active.

Planning for Complex Portfolios and Evolving Methods

Brands managing multiple SKUs face a scope-multiplication challenge. A single dataset covers a single product, production period, and analytical method. Extending one product’s result across a line is not supported by that dataset and is the most common way a rigorous finding turns into an indefensible claim.

Production changes, such as new suppliers, new packaging materials, or new filling lines, can affect the plastic content of a finished product in ways that a prior dataset does not capture. Any material change to production warrants a fresh look at whether the existing evidence still supports the claim.

Verification periods also have a practical ceiling. Lot-to-lot variability is a recognized challenge in microplastic analysis, and a result from one production period does not guarantee the next. A 24-month re-verification cycle, tied to the sampling date of the most recent accepted dataset, offers a reasonable framework for maintaining a claim that remains meaningful when a customer checks it.

Analytical methods continue to evolve. ISO 16094-2:2025 covers microplastics from 1 µm to 5,000 µm using vibrational spectroscopy, which extends the validated range compared to earlier methods. As methods improve, the evidence required to support a given claim may change, and brands with a repeatable verification framework can adapt more easily than those relying on a one-time laboratory report.

Frequently Asked Questions

How does a CCR differ from independent laboratory testing for microplastics?

A Consumer Confidence Report is an annual document that community water systems must publish. It covers regulated contaminants, meaning those with federal Maximum Contaminant Levels, detected in the utility’s water supply. Microplastics have no federal MCL, so they do not appear in CCRs.

Independent laboratory testing for microplastics is a separate, voluntary process commissioned by a brand or utility. It uses specialized analytical methods such as infrared or Raman spectroscopy. The two documents answer different questions and cannot substitute for each other when a plastic-reduction claim is at issue.

Can a brand rely on its own laboratory results for a microplastic reduction claim?

A brand can publish its own laboratory results, yet buyers, retailers, and consumers often discount self-reported data because it reads as marketing. The deeper issue is that a laboratory report alone does not show what the finding supports.

The report rarely clarifies whether the method was appropriate for the matrix, whether the reporting limits are adequate, whether blanks and controls were run correctly, and what claim the data can honestly carry. Independent review of the dataset against published criteria converts a laboratory report into a defensible market claim.

What happens if independent review does not support the claim?

With the Wellness Quality Institute’s Plastic-Free Pathway Verification, a Standard Not Met outcome remains private. It carries no public claim, no logo rights, and no registry listing. It is not described as a failed product and often reflects insufficient data, an unsupported analytical method, or incomplete scope rather than a product problem.

The company may submit corrected or additional information for future review. Participation in the review process creates no public downside risk, which is a deliberate design feature of the program.

Does “no microplastics detected” on a laboratory report mean a product is free of microplastics?

“None detected” means none were found above the instrument’s detection floor, for the polymer types it screened, in the production lot that was sampled. A method with a lower size limit of 50 micrometers cannot see anything smaller.

The California State Water Board’s regulatory definition of microplastics reaches down to 1 nanometer, which is thousands of times smaller than what current validated methods can reliably measure. A “none detected” result is a bounded finding, not a guarantee of absence, and no laboratory today can certify that any product is completely free of plastic across every particle size, polymer type, and production lot.

How long does a water quality or microplastic reduction claim stay valid after testing?

The validity of any claim tied to laboratory data is limited by the production period the data represents. Lot-to-lot variability means a result from one production run does not guarantee the next.

For brands seeking ongoing substantiation, a 24-month re-verification cycle tied to the sampling date of the most recent accepted dataset offers a practical framework. This approach helps ensure the claim reflects current production rather than a historical snapshot. Any material change to production, packaging, or suppliers warrants reassessment before the cycle ends.

Bringing Independent Verification Into Your Claims Strategy

National Water Quality Month highlights a consistent problem. Claims appear on packaging and websites faster than anyone can evaluate the evidence behind them. For regulated contaminants, Consumer Confidence Reports and EPA databases provide a starting point. For plastic and microplastic reduction claims, those sources do not apply, and the absence of a federal standard means the burden of substantiation falls entirely on the quality of the laboratory data and the independence of the reviewer.

The six-step playbook above gives brands and informed consumers a repeatable process for determining what any water quality claim actually supports. Independent review of the dataset by a party with no stake in the outcome remains the most important and most frequently skipped step.

The Wellness Quality Institute exists to fill that gap. The Institute’s Plastic-Free Pathway Verification program independently reviews a company’s existing laboratory data on plastic and microplastic content against defined criteria. The review produces a finding of either Standard Met or Standard Not Met, with approved claim language, a public registry entry, and a scope-locked license that keeps the claim inside what the evidence supports.

The program does not certify that any product is free of plastic. It verifies that a company is on a documented pathway toward plastic-free standards, which is the strongest claim the science can currently support and the only one worth making.

Connect with the Wellness Quality Institute to transform your testing results into verified, scope-appropriate claims.

WQI Plastic-Free Pathway Verification does not certify that a product contains zero plastic, microplastics, or nanoplastics. It shows that the company is on a verified pathway toward plastic-free standards. Verification applies only to the reviewed products, submitted datasets, tested ranges, polymer panels, production or sampling periods, and supporting controls. WQI verification is not a state approval, government certification, or health or safety certification.