Not on the chart: Rockville’s PFOS result was below the lab’s reporting limit, so it can’t be placed among the cities that detected it.
In Maryland, 5 of 31 city reports had a PFAS sample above a 2024 EPA limit. PFAS across Maryland →
Your tap usually reflects the system’s water, but results vary between samples and sources. Only a certified lab test tells you what reaches your glass today.
How to test for PFASPFAS are measured in parts per trillion. Home strips can’t read that low, so a certified lab is the only way to get a number for your tap.
These are the methods behind the federal results. Ask which compounds are on the panel, so PFBS, PFHxA and PFPeA are included, and keep the reporting limit with your result.
Find a certified lab in Maryland ↗ (opens in a new tab)No home strip has been shown to detect PFAS at the levels federal limits use. A mail-in lab kit is the closest at-home option; check that its lab is accredited and that its panel names the compounds you need.
Read your lab results →Why: these are the technologies certified to reduce PFAS. Certification is compound by compound, so check that a listing names the compound you need to reduce.
★ Best available: iSpring RCC7AK Alkaline Reverse Osmosis System, the best fit here; nothing in this group is certified yet.
| Pick | Product | Details and price | Certification | Why it’s listed | Link |
|---|---|---|---|---|---|
| ★ Best available | Reverse osmosisiSpring RCC7AK Alkaline Reverse Osmosis SystemUse code REFISPRING at checkout: 10% off your first iSpring order. | TechnologyReverse osmosisPrice$$ | Brand lab-tested, not independently certified for PFAS | See the evidence | Check price at iSpring |
| Also good | Reverse osmosisiSpring RO5004F Tankless Reverse Osmosis System with UVUse code REFISPRING at checkout: 10% off your first iSpring order. | TechnologyReverse osmosisPrice$$$ | Brand lab-tested, not independently certified for PFAS | See the evidence | Check price at iSpring |
| Also good | Reverse osmosisWaterdrop G3P600 Reverse Osmosis System | TechnologyReverse osmosisPrice$$$ | Brand lab-tested, not independently certified for PFAS | See the evidence | Check price at Waterdrop |
| Pick | Product | Details and price | Certification | Why it’s listed | Link |
|---|---|---|---|---|---|
| Also good | Reverse osmosisWaterdrop G3P800 Tankless Reverse Osmosis System | TechnologyReverse osmosisPrice$$$ | Brand lab-tested, not independently certified for PFAS | See the evidence | Check price at Waterdrop |
| Also good | Reverse osmosisWaterdrop X12 Reverse Osmosis System | TechnologyReverse osmosisPrice$$$$ | Brand lab-tested, not independently certified for PFAS | See the evidence | Check price at Waterdrop |
★ Best available: iSpring WGB32B-PFKS PFAS & Heavy Metals Whole House Filter, the best fit here; nothing in this group is certified yet.
| Pick | Product | Details and price | Certification | Why it’s listed | Link |
|---|---|---|---|---|---|
| ★ Best available | Whole-houseiSpring WGB32B-PFKS PFAS & Heavy Metals Whole House FilterUse code REFISPRING at checkout: 10% off your first iSpring order. | Price$$$ | Brand lab-tested, not independently certified for PFAS | See the evidence | Check price at iSpring |
Looking for regulated PFAS? Filters certified for PFOA and PFOS →
PurityMap earns a commission from these links. "Best choice" and "Budget pick" go to certified products first; commission never decides them. Affiliate disclosure.
PFBS, PFHxA, PFBA and PFPeA were found, but no federal limit exists to compare them with. The five regulated PFAS were below the lab’s reporting limit, which is not the same as zero. And 29 compounds were tested; PFAS not on that list have no result here.
Four PFAS were detected; none has a federal limit. In EPA UCMR 5 testing of CITY OF ROCKVILLE (2023-03-08 to 2023-12-04): PFBS 3.6 ng/L (EPA health advisory 2,000), PFHxA 5.8 ng/L (state limit 400,000), PFPeA 6.5 ng/L (no federal or state limit), PFBA 5.2 ng/L (no federal or state limit) and the other 25 PFAS tested not detected. "Not detected" means below the lab's reporting limit, not proven zero.
EPA's 2024 drinking-water rule set maximum contaminant levels of 4.0 ng/L for PFOA and for PFOS, and 10 ng/L for PFHxS, PFNA and HFPO-DA (GenX). In May 2026 EPA proposed keeping the PFOA and PFOS limits, with the option of until 2031 to comply, and rescinding the other three. Until a final rule, all five limits apply. The 2024 rule also set a Hazard Index of 1 for mixtures of two or more of PFHxS, PFNA, GenX and PFBS; EPA has proposed rescinding it, and it applies until a final rule.
No. They have no federal drinking-water limit (MCL); the 2024 rule sets limits only for PFOA, PFOS, PFHxS, PFNA and HFPO-DA (GenX). PFBS has no limit of its own; the 2024 rule counts it only inside the Hazard Index for mixtures, which EPA has proposed rescinding. PFBS has an EPA health advisory of 2,000 ng/L, a screening level, not a legal limit. PFHxA has a 400,000 ng/L state limit. Rockville's results: PFBS 3.6 ng/L, PFHxA 5.8 ng/L, PFPeA 6.5 ng/L and PFBA 5.2 ng/L.
No. "Not detected" (ND) means the result was below the lab's reporting limit, not that the compound is absent. In Rockville's record, 25 of the 29 PFAS tested were not detected. Their reporting limits run from 2 to 20 ng/L.
29 PFAS compounds in EPA UCMR 5 testing of CITY OF ROCKVILLE (2023-03-08 to 2023-12-04), including the five with federal limits. PFBS, PFHxA, PFPeA and PFBA were detected. PFAS not on that list have no result here.
Yes. These results describe the water system as a whole, and levels vary between samples and sources over time. PFAS come with the water rather than from home plumbing, so your tap usually reflects the system's water, but only a certified lab test of your own tap gives a number for your glass.
Use a state-certified lab that runs EPA Method 533 or 537.1, the methods behind the federal results. Ask which compounds are on the panel, so PFBS, PFHxA and PFPeA are included, and keep the reporting limit with your result. No home test strip has been shown to detect PFAS at the levels federal limits use.
Reverse osmosis (NSF/ANSI 58), activated carbon (NSF/ANSI 53) and anion exchange can reduce PFAS, but certification is compound by compound. Choose a model whose current listing names the compound you need to reduce, here PFBS, PFHxA and PFPeA, check it in the certifier's listing (NSF, WQA or IAPMO), and replace cartridges on schedule.
Look for PFBS, PFHxA and PFPeA by name in the certifier's listing (NSF, WQA or IAPMO) for the exact model: NSF/ANSI 53 and 58 listings name each PFAS a filter was tested to reduce. A listing for PFOA and PFOS alone does not cover PFBS, PFHxA and PFPeA.
Compliance with the 2024 limits is judged on a running annual average, with a compliance date of 2029 (EPA has proposed allowing until 2031 for PFOA and PFOS). EPA has proposed rescinding the PFHxS, PFNA, GenX and Hazard Index limits; they apply until a final rule.