Key Takeaways
- PFAS monitoring is currently underway for Colorado public water systems face compliance monitoring deadlines tied to the EPA’s 2024 PFAS MCL rule.
- EPA Method 533 and 537.1 is the primary approved method for PFAS in finished drinking water and the method most relevant to initial compliance monitoring.
- SPL Commerce City now offers Method EPA 533 analysis, providing Colorado utilities with an in-region certified testing option.
- SPL Reading, PA supports expanded method coverage, including Methods 533, 537.1, and 1633 for wastewater, soil, and non-drinking water matrices.
- A compliant PFAS monitoring program starts with method selection, sample frequency planning, and a lab partner who understands your regulatory context.
- PLUS – Register for our FREE June 12th Webinar AND Download our FREE eBook on Sampling Success.
When the EPA finalized its PFAS Maximum Contaminant Levels in April 2024, it started a compliance clock that Colorado public water systems cannot afford to ignore. Six PFAS compounds now have enforceable MCLs. Systems must complete initial monitoring. And the 2027 compliance deadline is close enough that the decisions you make this year about lab partners, methods, and monitoring frequency will determine whether your system is positioned for defensible reporting or scrambling for capacity when everyone else needs it at the same time.
Monitoring frequency under the final rule depends on system size and source water type at each entry point, with initial sampling requirements set on either a twice-yearly or quarterly basis within a 12-month window.
Surface water systems serving any population size, along with groundwater systems serving more than 10,000 people, are required to collect four consecutive quarterly samples over a 12-month period, with each sample collected two to four months apart. Groundwater systems serving 10,000 or fewer people must collect two samples within the same 12-month timeframe, spaced five to seven months apart.
In Part 1 of this series, we introduced SPL Commerce City, its Principal State Laboratory designation, and the facility’s role in Colorado’s environmental testing infrastructure. In Part 2, we get into the specifics of PFAS compliance monitoring: what the regulations require, which methods apply to which matrices, and how to structure a monitoring program that generates defensible data.
What the EPA PFAS Rule Actually Requires
The April 2024 final rule sets MCLs for six PFAS compounds: PFOA (4 ppt), PFOS (4 ppt), PFNA, PFHxS, HFPO-DA (GenX), and PFBS. For PFHxS, PFNA, HFPO-DA, and PFBS, the rule establishes a Hazard Index with a combined limit of 1.0 when any combination of those four is present.
Public water systems using surface water or groundwater under the direct influence of surface water must monitor for all six compounds in Colorado. Systems above detection thresholds will be required to provide public notification and, eventually, treatment.
Initial monitoring must use approved EPA methods, and results must be reported to state primacy agencies. The compliance date for treatment is April 2027.
Method Selection: Which Test for Which Situation
Not all PFAS methods are the same, and the choice of method matters for regulatory acceptance, analyte coverage, and cost-efficiency.
- EPA Method 533: Best for drinking water when expanded short-chain PFAS coverage is needed beyond 537.1’s scope. Covers 25 analytes. Available at SPL Commerce City, CO and Reading, PA.
- EPA Method 537.1: Best for finished drinking water compliance monitoring. Covers 40+ PFAS including all six regulated compounds. Available at SPL Reading, PA.
- EPA Method 1633: Best for wastewater, biosolids, soil, sediment, groundwater, and tissue. Covers 40+ PFAS across complex matrices. Available at Reading, PA.
For most Colorado public water systems beginning their initial compliance monitoring, Method 533 is the starting point. If your system wants to screen for short-chain PFAS beyond 537.1’s scope, or if you are also managing wastewater or industrial discharge with PFAS concerns, our lab in Reading, PA’s multi-method capability gives you options within one lab network, and you can submit your samples at any of our SPL Environmental labs for analysis.
Building a Compliant PFAS Monitoring Program
A functional PFAS monitoring program has three components: a sampling plan, a lab agreement, and a reporting chain.
1. Sampling Plan – Define your entry points, sample frequency, and collection protocols. Initial monitoring under the final rule is typically one year of quarterly sampling at each entry point, though some systems may qualify for reduced monitoring. Chain-of-custody documentation and proper containers (polypropylene or HDPE; no PTFE or glass) matter for method validity.
2. Lab Agreement – Your lab must be certified for the method and matrix you are submitting. Confirm turnaround time, detection limits, and whether the lab’s reporting format will meet your state agency’s data submission requirements. SPL Commerce City holds Colorado state certification and EPA Region 8 designation. SPL Reading, PA holds multi-state certifications relevant to multi-matrix PFAS work.
3. Reporting Chain – Know how your state primacy agency wants data formatted and delivered. Many states use an electronic data deliverable (EDD) format. Ask your lab early. Data that cannot be submitted in the required format is data that does not count.
Why Capacity Matters as Much as Capability
One thing the PFAS compliance wave has exposed is that lab capacity is not infinite. As 2027 approaches, demand for certified PFAS analysis will increase across every state simultaneously. Utilities that establish lab agreements in 2025 and 2026 will be in a stronger position than those who wait for the crunch.
SPL Commerce City‘s designation as a Principal State Laboratory reflects not just method capability but scalable capacity. The lab was built to absorb increased throughput without sacrificing turnaround or data quality. That distinction matters when every municipality in Colorado needs results on the same compliance timeline.
What Colorado Systems Should Be Doing Now
1. Confirm which PFAS compounds your system must monitor for based on source water type and system size.
2. Identify your entry points and establish a sampling schedule that meets initial monitoring requirements.
3. Engage a certified lab. Get method confirmation, turnaround commitments, and EDD format specifications in writing.
4. Register for SPL’s June 12th webinar to hear Lauren Hevert walk through compliance program structure and answer your specific questions.
5. Download the free PFAS section of the Definitive Guide for Drinking Water and Wastewater Operators for a plain-language compliance reference.
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Register for the June 12 Webinar: PFAS Compliance Q&A with Lauren Hevert
Free Zoom Webinar |Â Join us on June 12, 2026 at 11AM MT (1 ET, 12 CT)
Download our FREE Ebook
The Definitive Guide for Drinking Water and Wastewater Operators including bonus PFAS section
The 2027 compliance timeline is not a future problem. It is a current operational decision about which lab you choose, how many samples you plan, and whether your data will withstand regulatory review. SPL Commerce City is ready to support that work today, with Method 537.1 capability, Colorado-state certification, and a team that understands what your reporting obligations actually require.
 Download the PFAS Capability Flyer | Quick-reference PDF
Frequently Asked Questions
What EPA methods does SPL use for PFAS testing?
SPL uses EPA Method 533 and EPA Method 537.1 for drinking water compliance analysis, and EPA Method 1633 for non-potable water (wastewater, groundwater, surface water, leachate) and solid matrices including soil, sediment, and biosolids. Method selection depends on your matrix, regulatory program, and detection level requirements. Contact SPL’s laboratory team for a method recommendation specific to your program.
Which SPL laboratories perform PFAS testing?
PFAS analysis is performed at two SPL accredited laboratory facilities:
Reading, PA: EPA Methods 533 and 537.1 (drinking water); EPA Method 1633 (non-potable water and solids)
Commerce City, CO: EPA Method 533 (drinking water)
Sample acceptance is available through all SPL Environmental locations nationwide. Contact your local SPL representative or submit samples directly to the designated analytical facility.
What is the current EPA MCL for PFAS in drinking water?
The U.S. EPA finalized Maximum Contaminant Levels (MCLs) of 4 parts per trillion (ppt) for PFOA and PFOS in its April 2024 National Primary Drinking Water Regulation. EPA has confirmed it will retain these MCLs and has announced plans to extend the compliance deadline for public water systems to 2031.Â
EPA has indicated intent to rescind the separately established MCLs for PFHxS, PFNA, HFPO-DA (GenX), and the Hazard Index mixture provision — however, state-level regulations remain in effect and may require monitoring for these additional compounds. Contact SPL for guidance on state-specific requirements in your service area.
What is the difference between EPA Method 533 and EPA Method 537.1?
Both methods are approved for drinking water compliance under the Safe Drinking Water Act (SDWA) and are the only two EPA methods accepted for formal MCL compliance reporting in drinking water.
EPA Method 533 uses isotope dilution and is the preferred method for detecting short-chain PFAS (PFBS, GenX/HFPO-DA). It has fewer QC failures and is recommended by PADEP for compliance programs.
EPA Method 537.1 analyzes 18 PFAS compounds and is widely used for standard compliance reporting. It is slightly more economical but carries higher risk of QC failures requiring re-sampling.
SPL recommends Method 533 for most drinking water compliance programs. The two methods are not interchangeable — confirm which method is specified by your state regulatory program.
Can EPA Method 1633 be used for drinking water compliance?
No. EPA Method 1633 is not accepted for drinking water MCL compliance reporting under the Safe Drinking Water Act — EPA Methods 533 and 537.1 are the only approved methods for SDWA compliance. However, EPA Method 1633 may be used for non-compliance investigative monitoring of drinking water sources (e.g., source water screening) and is the standard method for non-potable water and solid matrices under Clean Water Act programs.
Does SPL provide PFAS-free sampling containers and collection kits?
Yes. SPL provides certified PFAS-free sampling containers, chain-of-custody documentation, and detailed collection instructions for each matrix type. This is not optional — PFAS can leach from standard polyethylene and glass laboratory containers, contaminating samples and generating false positive results. Always use containers supplied by SPL or another accredited PFAS laboratory.
Contact SPL to request a sampling kit before collecting samples for PFAS analysis.
What is a Field Reagent Blank (FRB) and is it required?
A Field Reagent Blank (FRB) is collected at the sample site using laboratory-supplied reagent water and the same containers used for the environmental sample. It is required by the method, and serves as a quality control check to detect any PFAS contamination introduced during the collection process. An FRB is required for all drinking water PFAS compliance submissions under both EPA Methods 533 and 537.1. SPL’s sampling kits include the materials needed to collect an FRB at each sampling event.
How do I submit samples to SPL for PFAS testing?
Samples can be submitted through any SPL service location, or shipped directly to the designated analytical laboratory. To get started:
- Contact SPL to request a quote and method recommendation
- SPL ships certified PFAS-free sampling containers and chain-of-custody forms
- Collect samples following SPL’s protocol (FRBs required for drinking water compliance)
- Submit samples with completed chain-of-custody to your nearest SPL location or directly to the lab
- Access results via SureVue/WebLDS online portal
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Whether you're navigating compliance deadlines, investigating a contaminated site, or establishing a baseline monitoring program, SPL is ready to support your PFAS testing needs with accredited methods, certified sampling infrastructure, and defensible data delivered through 30+ locations nationwide.