How Can PFAS enter Bottled Water?

PFAS can enter bottled water from several specific, well-documented sources. These fall into three main categories: source-water contamination, processing equipment, and packaging. Here is a clear breakdown used by regulators, labs, and recent academic studies.

1. Contaminated Source Water (Most Significant Source)

PFAS are persistent and widespread, so they often show up in:

a. Groundwater / Aquifers

• PFAS migrate easily through sandy or fractured soils.

• Common near airfields, military bases, metal plating facilities, and landfills.

• Many “spring water” products come from aquifers that may already contain trace PFAS.

b. Surface Water (rivers, lakes)

• Impacted by upstream wastewater treatment plants, industrial discharges, and stormwater.

c. Municipal Water Used by Bottling Plants

• Some bottlers fill bottles with filtered municipal tap water, and if the city supply contains PFAS, the bottled product can too.

  
  

2. Bottling Plant & Treatment Equipment

Even when source water is relatively clean, PFAS can enter during treatment or bottling.

a. Filters, membranes, and resins

• Certain treatment media (e.g., some polymeric membranes) can shed trace PFAS residuals during wear or degradation.

• If RO membranes or GAC are not maintained, PFAS can break through.

b. Bottling plant plumbing & piping

• PTFE (Teflon) coatings, gaskets, and fluoropolymer parts may leach ultra-short-chain PFAS, especially at high temperature or pressure.

c. Airborne PFAS inside facilities

• PFAS from cleaning products or packaging materials can settle into open bottles before sealing.

3. Packaging Materials (Less common but possible)

a. Plastic bottles (PET)

• PET itself does not contain PFAS.

• However, manufacturing aids used in plastic molding, slip agents, or lubricants may contain PFAS residues at very low levels.

b. Bottle caps & liners

• Some caps use fluoropolymer-based coatings for sealing.

• These can release ultra-short PFAS under certain conditions.

c. Aluminum cans with plastic liners

• Beverage cans use epoxy or polymer liners that sometimes incorporate fluorinated processing aids.

d. Cardboard / carton packaging

• Laminated cartons (e.g., boxed water) may use PFAS-treated paperboard for water resistance, depending on the manufacturer. 

Which sources matter most?

Based on testing from independent labs, EPA, EWG, and academic work:

1. Source water contamination → by far the most frequent cause

2. Treatment system breakthrough → common when RO/GAC is undersized or exhausted

3. Packaging → possible but generally low contributor

4. Plant contamination → low but documented occasionally

Here’s a practical guide to choosing bottled water with lower microplastic exposure — based on available scientific studies and measured contamination levels. Microplastics are present in almost all bottled water, but some types and packaging choices can reduce your exposure. (PubMed)

🧊 What Research Shows About Microplastics in Bottled Water

✔ Most bottled water (~90–95% of samples) contains microplastic particles. (PubMed)✔ Counts vary widely between brands — from a few particles per liter up to thousands per liter, depending on testing method. (SpringerLink)✔ Newer studies that detect nanoplastics (tiny particles <1 µm) find much higher totals (hundreds of thousands per liter). (National Institutes of Health (NIH))✔ Even water in glass bottles can contain microplastics, often from caps and seals. (ScienceDirect)