PFAS in Rainwater Collection: Is It Safe to Harvest Rain?

If you collect rainwater at home, you might assume it is about as clean as water gets. But PFAS (per- and polyfluoroalkyl substances, often called “forever chemicals”) have been found in rainwater samples worldwide, sometimes at levels that exceed drinking water guidelines. The contamination comes from industrial emissions that cycle through the atmosphere, so geography alone does not protect you. Here is what we know and what you can do about it.

For more on PFAS-free living, see our guide to PFAS blood testing and PFAS free silicone cookware.

What Does the Science Say About PFAS in Rainwater Collection?

A 2022 study in Environmental Research found PFAS in rainwater samples across multiple continents, with concentrations that often exceeded the EPA’s health advisory levels. The problem is that PFAS do not break down in the atmosphere. They travel on air currents, bind to rain droplets, and end up in your barrel or cistern. Your body eliminates them slowly (half-lives of several years for some compounds), so even low-level exposure from collected rainwater adds to what you are already getting from food, dust, and tap water.

How to Identify PFAS-Free Rainwater Collection Products

Labels rarely tell the whole story. Most U.S. states do not require manufacturers to disclose PFAS on product packaging, so you have to dig a little deeper.

Third-party certifications are your best shortcut. OEKO-TEX Standard 100, bluesign, and GOTS all prohibit PFAS in certified products. If a product says “water-resistant” or “stain-resistant” but carries none of these certifications, that is a red flag for fluorinated coatings.

When in doubt, email the manufacturer and ask specifically about fluorinated treatments. Companies that have moved away from PFAS are usually happy to say so. You can also search the PFAS Free Life Database for products that have already been checked.

Safe Rainwater Collection Recommendations

The most important step for any rainwater harvesting setup is filtration. Collected rain may look clean, but PFAS are invisible and odorless. A quality water test is a good starting point so you know what you are actually dealing with.

The Tap Score Advanced Home Water Test Kit tests for over 100 contaminants including PFAS. It is a mail-in lab kit, so you get EPA-certified results rather than a rough estimate from a test strip.

For the collection system itself, stick with stainless steel or glass components where possible. Both materials are inert and will not leach PFAS. If you use plastic barrels or liners, look for ones that carry OEKO-TEX or similar certifications confirming no fluorinated treatments were applied.

Tips to Reduce PFAS Exposure in Your Rainwater Collection System

Filtration is your biggest lever, but a few other habits help too.

Open windows regularly. PFAS settle into household dust, and young children who play on the floor get a disproportionate dose. Washing new collection equipment before first use can also reduce surface chemical residues.

If you use harvested rainwater for drinking or cooking, a reverse osmosis system is the most reliable way to remove PFAS. Activated carbon filters catch some compounds but miss shorter-chain variants. We compared options in our guide to top PFAS free water filters, and the PFAS Free Life Database lists specific models that have been tested.

Frequently Asked Questions

Do all rainwater collection products contain PFAS?

No, not all rainwater collection products contain PFAS. However, many products that are marketed as water-resistant, stain-resistant, or non-stick have historically used PFAS-based treatments. The safest approach is to look for third-party certifications like OEKO-TEX Standard 100 or to contact the manufacturer directly to ask about their chemical policy.

Are PFAS-free rainwater alternatives effective?

Yes, PFAS-free alternatives have improved significantly in recent years. Natural materials like stainless steel, cast iron, glass, and untreated natural fibers perform well without any chemical coatings. For water-resistant textiles, fluorine-free DWR treatments have become widely available and work well for everyday conditions. Many families find the alternatives work just as well once they make the switch.

Can I test my home for PFAS contamination?

Yes. You can test your drinking water for PFAS using certified laboratory testing services or at-home kits from companies like SimpleLab. For other types of exposure, from products or household dust, testing is more complex, but starting with your water is the most impactful first step. Your state health department may also offer resources or low-cost testing programs.