Blog

‹ Back

Walk into almost any school built or renovated in the last decade and you’ll find a bottle-filling station. Many are made by Elkay, and many now carry a filter labeled for PFAS reduction. Parents see “PFAS” and reasonably assume the “forever chemicals” are handled.

The label is honest. But it covers less than most people think, and the gap matters most for the PFAS that are hardest to filter.

What the certifications say

• Elkay WaterSentry 71300C (the PFAS filter for Enhanced ezH2O bottle fillers): certified to NSF/ANSI 42 and 53 for reducing PFOA and PFOS, plus lead. Elkay itself describes these as “two prevalent PFAS chemicals.” Replace every 2,250 gallons or one year.

• Elkay Pro Filtration FLP4 (newer, 4,000 gallons): labeled “Total PFAS as defined by NSF/ANSI 53.” Under that standard, “Total PFAS” means seven compounds: PFOA, PFOS, PFHxS, PFNA, PFHpA, PFBS and PFDA.

The PFAS family includes thousands of chemicals. Only one of those seven, PFBS, is a short-chain PFAS. Not on either list: PFBA, PFPeA, PFHxA, or GenX (HFPO-DA), the short-chain and replacement chemicals industry moved to after PFOA and PFOS were phased out.

Why short-chain PFAS slip past carbon

Short-chain PFAS have smaller molecules. They move easily through water and stick less tightly to activated carbon, the material in most point-of-use filters. In a pilot study of carbon filtration, shorter-chain PFAS broke through sooner than longer-chain ones (Liu, Werner and Bellona, 2019).

So a filter certified for PFOA and PFOS may reduce some short-chain PFAS, or very little. The certification simply doesn’t test for them, so it can’t tell you. This is not a claim that any specific Elkay filter fails. It is that the label doesn’t answer the question parents are asking. To Elkay’s credit, it certifies more than many filters on the market do.

What the rules cover

The EPA’s 2024 drinking-water rule set limits of 4 parts per trillion for PFOA and PFOS, with compliance due in 2029. In May 2026, EPA proposed giving water systems until 2031, and proposed rescinding the limits for PFHxS, PFNA, GenX and the PFBS mixture. If that goes through, the federal rule would cover only PFOA and PFOS, the same two compounds most school filters are certified for.

Why this matters for children

Children drink more water for their body weight than adults, and at school they may fill a bottle several times a day from the same station. That’s a good habit we want to protect, which is exactly why the water deserves a clear answer.

Questions parents and schools can ask

1. Which filter is installed, and what is it certified for? The model number is on the cartridge. Look for the exact compounds, not just “PFAS.”

2. When was it last changed? Most fillers have a filter light or gallon counter. An expired filter protects against nothing.

3. Has the school’s water been tested for short-chain PFAS? Ask for a certified lab test that reports compounds like PFBA, PFHxA and GenX, not only PFOA and PFOS.

4. Could drinking stations use reverse osmosis? Reverse osmosis (RO), a membrane filter much finer than carbon, generally reduces a much broader range of PFAS, including many short-chain ones. An RO refill station can send its leftover water to the restrooms next door, so nothing is wasted. That’s a design we’re working on for schools.

The goal isn’t to scare anyone away from refill stations. It’s to make sure “PFAS certified” means what parents think it means.

— Raymundo Razon Abad, civil engineer

Sources

• Elkay, WaterSentry 71300C product page

• Zurn Elkay press release, December 12, 2023

• Elkay, Pro Filtration FLP4 product page

• WaterWorld: NSF adds PFAS compounds to NSF/ANSI 53 and 58

• Liu, Werner and Bellona (2019), Environmental Science: Water Research & Technology

• Congressional Research Service: EPA’s PFAS Drinking Water Regulation (June 2026)