A common misconception is that boiling water purifies it from chemical contaminants the same way it eliminates pathogens. For PFAS, this belief is dangerously incorrect: boiling water does not remove PFAS and may actually increase their concentration.
Why Boiling Doesn’t Remove PFAS
Boiling is effective against biological contaminants — bacteria, viruses, and protozoa — because heat denatures proteins and disrupts cell membranes. Chemical contamination is a fundamentally different problem. PFAS compounds have high boiling points and very low vapor pressures. At the 100°C boiling point of water, PFAS molecules remain dissolved in the liquid phase rather than volatilizing with steam.
Concentration Effect From Boiling
Boiling water causes evaporation. As water volume decreases, dissolved contaminants including PFAS become more concentrated in the remaining liquid. Boiling a pot of PFAS-contaminated water until half the volume has evaporated roughly doubles the PFAS concentration per liter. For households using boiling as a purification strategy, this represents a meaningful increase in exposure rather than a reduction.
What Boiling Does Address
Boiling remains the correct response to boil-water advisories issued for biological contamination — when pipes break or flooding introduces pathogens. These events do not change the underlying PFAS situation, and separate filtration remains necessary for PFAS reduction. During a boil-water advisory in a PFAS-affected area, the appropriate response is to use previously filtered or certified bottled water for drinking while boiling for biological safety as directed by authorities.