​​PFAS Drinking Water Testing & Analysis | PFOA, PFOS, PFHxS, PFCAs, PFSAs & Fluorotelomer Sulfonates

Professional PFAS Water Sampling, Laboratory Analysis & Environmental Testing | US Environmental Testing LLC (USENVI)

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What Are PFAS and Why Should Drinking Water Be Tested?

Per- and polyfluoroalkyl substances (PFAS) are a large family of synthetic chemicals used in manufacturing, industrial processes, firefighting foams, water-resistant coatings, food packaging, textiles, and numerous consumer products. PFAS are often called forever chemicals because many are extremely persistent in the environment and can remain in groundwater, surface water, soil, and drinking water for extended periods.

PFAS contamination is an important drinking water concern for municipal water systems, private wells, commercial properties, industrial facilities, schools, healthcare facilities, property owners, and real estate transactions.

US Environmental Testing LLC (USENVI) provides professional environmental sampling coordination and PFAS drinking water testing services to help identify and evaluate potential contamination. Our testing programs can include perfluorocarboxylic acids (PFCAs), perfluorosulfonic acids (PFSAs), and selected fluorotelomer sulfonates (FTSAs), depending on the analytical method and requested laboratory analyte list.

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Understanding the Three Major PFAS Chemical Groups

1. PFCAs – Perfluorocarboxylic Acids

PFCAs are a major group of PFAS characterized by a perfluorinated carbon chain attached to a carboxylic acid functional group. They have been used in industrial manufacturing, fluoropolymer production, surface treatments, and other chemical applications.

Common PFCAs include:

• PFOA (Perfluorooctanoic Acid): A historically widespread PFAS associated with fluoropolymer manufacturing and industrial applications.

• PFBA (Perfluorobutanoic Acid)

• PFPeA (Perfluoropentanoic Acid)

• PFHxA (Perfluorohexanoic Acid)

• PFHpA (Perfluoroheptanoic Acid)

• PFNA (Perfluorononanoic Acid)

• PFDA (Perfluorodecanoic Acid)

• PFUnDA and PFDoDA

PFOA is one of the most extensively studied PFAS compounds and is a significant contaminant of concern in drinking water investigations.

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2. PFSAs – Perfluorosulfonic Acids

PFSAs are PFAS compounds containing a perfluorinated carbon chain attached to a sulfonic acid functional group. These chemicals have been used in stain-resistant treatments, surface coatings, firefighting formulations, and industrial applications.

Common PFSAs include:

• PFOS (Perfluorooctanesulfonic Acid): A historically important PFAS used in numerous industrial and commercial applications.

• PFHxS (Perfluorohexanesulfonic Acid): A persistent PFAS associated with historical firefighting foam and industrial applications.

• PFBS (Perfluorobutanesulfonic Acid)

• PFPeS (Perfluoropentanesulfonic Acid)

• PFHpS (Perfluoroheptanesulfonic Acid)

PFOS and PFHxS are important target analytes when evaluating drinking water contamination and potential historical industrial or firefighting foam impacts.

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3. FTSAs – Fluorotelomer Sulfonates

Fluorotelomer sulfonates are a related group of polyfluorinated substances that can be associated with industrial applications, firefighting foams, surface treatments, and certain fluorinated products.

Unlike fully perfluorinated PFCAs and PFSAs, fluorotelomer sulfonates contain a partially fluorinated carbon chain. They are important because some can undergo environmental transformation into other persistent PFAS compounds.

Common target analytes include:

• 4:2 FTSA (4:2 Fluorotelomer Sulfonate)

• 6:2 FTSA (6:2 Fluorotelomer Sulfonate)

• 8:2 FTSA (8:2 Fluorotelomer Sulfonate)

The numerical designation identifies the fluorinated and non-fluorinated carbon portions of the fluorotelomer structure. These compounds can provide additional information during investigations involving AFFF firefighting foam, industrial wastewater, groundwater, and other potential PFAS sources.

Important: Not every PFAS laboratory method measures every chemical group. The requested analyte list must be verified before sampling and laboratory submission.

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Which EPA Method Is Used for PFAS Drinking Water Testing?

PFAS analysis typically uses liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The appropriate EPA method depends on the sample matrix, target compounds, and whether the testing is intended for regulatory compliance or environmental investigation.

EPA Method Primary Application Analytical Coverage

EPA Method 533 Drinking water25 selected PFAS, including short-chain PFAS and selected fluorotelomer sulfonates

EPA Method 537.1, Version 2.0Drinking water18 selected PFAS, including PFOA, PFOS, and PFHxS

EPA Method 1633 Broader environmental matrices40 selected PFAS in groundwater, surface water, wastewater, soil, sediment, biosolids, landfill leachate, and fish tissue

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EPA Method 533 – Expanded Drinking Water PFAS Analysis

EPA Method 533 uses isotope-dilution solid-phase extraction (SPE) and LC-MS/MS to identify and quantify selected PFAS in drinking water.

This method is particularly important when evaluating a broader group of PFAS, including short-chain compounds and fluorotelomer sulfonates.

Method 533 includes 4:2 FTSA, 6:2 FTSA, and 8:2 FTSA, making it an important method when these compounds are specifically requested.

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EPA Method 537.1 – Drinking Water PFAS Analysis

EPA Method 537.1 Version 2.0 uses solid-phase extraction and LC-MS/MS to analyze 18 selected PFAS in drinking water.

It includes important compounds such as PFOA, PFOS, and PFHxS. It is an EPA-approved drinking water method and is used in regulatory monitoring programs.

Method 537.1 does not provide the same expanded FTSA coverage as Method 533.

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EPA Method 1633 – Broader Environmental PFAS Testing

EPA Method 1633 is designed for PFAS analysis in a broader range of environmental matrices, including groundwater, surface water, wastewater, soil, sediment, biosolids, landfill leachate, and fish tissue.

It analyzes 40 selected PFAS using LC-MS/MS.

Method 1633 should not be confused with the approved drinking water compliance methods. For regulated public drinking water monitoring, Methods 533 and 537.1 are the applicable EPA-approved methods. Additional analytes must be confirmed against the method-specific target list.

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PFAS Reporting Limits: What Does Parts Per Trillion Mean?

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PFAS concentrations in drinking water are commonly reported in parts per trillion (ppt), equivalent to nanograms per liter (ng/L).

A single part per trillion represents approximately one drop of water in 20 Olympic-sized swimming pools. This illustrates why specialized laboratory equipment and contamination-controlled sampling procedures are essential.

Typical drinking water PFAS reporting sensitivity may be in the low single-digit ppt range, depending on the compound, analytical method, laboratory validation, and sample matrix.

Measurement Equivalent Concentration

• 1 ppt1 ng/L

• 2 ppt2 ng/L

• 4 ppt4 ng/L

• 5 ppt5 ng/L

• 10 ppt10 ng/L

• 1 ppb1,000 ppt

Minimum Reporting Levels (MRLs), Method Detection Limits (MDLs), and laboratory Reporting Limits (RLs) are not interchangeable. The actual reporting limit must be obtained from the performing laboratory for each analyte and analytical batch.

For example, EPA's UCMR 5 monitoring program established minimum reporting levels of 3 ppt for 4:2 FTSA and 5 ppt for both 6:2 FTSA and 8:2 FTSA under Method 533. These are program-specific levels, not a guarantee of every laboratory's reporting limits.

USENVI recommends reviewing the laboratory's analyte-specific reporting limits before collecting samples, particularly when evaluating results against drinking water standards or health-based advisory levels.

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PFAS Drinking Water Sampling Requirements & Quality Control

PFAS sampling requires specialized collection procedures because PFAS-containing materials are common in everyday products and sampling equipment. Improper handling can introduce contamination and compromise analytical results.

Professional PFAS sampling should follow the laboratory's approved collection instructions and applicable EPA guidance.

Essential PFAS Sampling Rules

1. Use PFAS-Free Sample Bottles

Use laboratory-supplied, approved polypropylene or polyethylene sample containers with compatible caps. Bottles must be appropriate for the analytical method and laboratory requirements. Do not substitute ordinary water bottles or containers.

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2. Avoid Teflon and Fluoropolymer Materials

Teflon, PTFE, and other fluoropolymer-containing materials must be avoided during sample collection wherever possible. This includes tubing, sample-contact equipment, certain seals, tape, and other potentially contaminating materials.

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3. Collect Field Blanks

A field reagent blank (FRB) is used to evaluate potential contamination introduced during transportation, handling, and field collection. The laboratory provides PFAS-free reagent water and the appropriate blank container and instructions.

Additional equipment blanks or field duplicates may be required depending on the sampling plan.

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4. Maintain Chain of Custody

Every sample must have appropriate identification and documentation, including:

• Unique sample identification number

• Collection date and time

• Sampling location and source

• Requested EPA analytical method

• Requested PFAS analyte list

• Sampler identification

• Sample preservation and temperature requirements

• Laboratory chain-of-custody documentation

• Sample receipt and transfer records

Chain-of-custody documentation establishes sample traceability from collection through laboratory receipt and analysis.

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5. Prevent Cross-Contamination

Avoid personal care products, cosmetics, sunscreen, insect repellents, water-resistant clothing, stain-resistant materials, and other potential PFAS sources during collection. Do not touch the inside of sample bottles or caps. Follow laboratory requirements for gloves, coolers, ice, and sample storage.

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6. Follow Laboratory Preservation and Shipping Requirements

Samples must be collected in the correct containers, preserved as required by the method, and shipped under the laboratory's specified temperature and holding-time conditions. Do not rinse or overfill prepared sample containers.

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How Are Public Water Systems Sampled for PFAS?

Public water system sampling must be conducted according to the applicable regulatory monitoring plan, approved analytical method, and state drinking water requirements.

For regulated public water systems, sampling locations commonly include entry points to the distribution system (EPTDS), where treated water enters the distribution network.

A typical sampling program involves:

1. Reviewing the water system's identification, treatment configuration, and regulatory monitoring requirements.

2. Identifying the required entry points and sampling locations.

3. Reviewing the laboratory sampling kit, analyte list, and collection instructions.

4. Collecting the required drinking water samples and associated field reagent blanks.

5. Completing sample identification, field documentation, and chain-of-custody records.

6. Transporting samples to the qualified laboratory under required conditions.

7. Reviewing analytical reports and comparing results with applicable regulatory requirements.

For a public water system with multiple entry points, sampling requirements may apply separately to each designated location. The number and frequency of samples depend on the regulatory monitoring schedule and system-specific requirements.

Private well, residential tap, commercial building, and industrial facility sampling follow different project-specific sampling plans. A residential drinking water sample should not automatically be treated as a public water system compliance sample.

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Who Should Consider PFAS Drinking Water Testing?

PFAS testing may be appropriate for:

• Municipal and community public water systems

• Private residential wells

• Commercial and industrial facilities

• Schools, colleges, and daycare facilities

• Hospitals and healthcare facilities

• Real estate transactions and property due diligence

• Properties near manufacturing facilities

• Properties near airports and military installations

• Locations with historical AFFF firefighting foam use

• Groundwater investigations and environmental assessments

• Wastewater treatment and industrial discharge investigations

Testing can help determine whether selected PFAS compounds are present in drinking water and provide analytical information for further investigation.

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Schedule Professional PFAS Drinking Water Sampling with USENVI

US Environmental Testing LLC (USENVI) provides environmental testing services designed to help property owners, businesses, water systems, real estate professionals, and industrial clients evaluate potential environmental contaminants.

Our PFAS testing services can be coordinated around EPA analytical methods, laboratory-specific analyte lists, reporting limits, sampling requirements, and project-specific quality assurance procedures.

Whether you need PFOA testing, PFOS testing, PFHxS testing, expanded PFAS analysis, or testing for 4:2, 6:2, and 8:2 fluorotelomer sulfonates, selecting the correct analytical method and following proper sampling procedures are essential to obtaining meaningful results.

 

Request PFAS Drinking Water Testing

US Environmental Testing LLC (USENVI)
Website: https://www.usenvi.com
Phone: 331-462-7211
Email: info@usenvi.com

USENVI – Professional Environmental Testing, Sampling & Laboratory Analysis Coordination.

 

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References:

1. EPA – Drinking Water Research Methods — EPA descriptions of Methods 533, 537.1 and 1633.

2. EPA – PFAS Drinking Water Laboratory Methods — Approved drinking water analytical methods.

3. EPA – PFAS Drinking Water Sampling Requirements (June 2025) — Sampling kits, field reagent blanks and contamination prevention.

4. EPA – UCMR 5 Monitoring Requirements — Specific FTSA monitoring and reporting levels.

5. EPA – Comparing PFAS Drinking Water Analytical Methods — Comparison of drinking water analyte coverage.

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