Quick take
Point-of-use PFAS treatment can start in the low hundreds. Whole-house PFAS treatment can move into the low thousands because of media volume, flow rate and installation.
Lowest-cost path: certified point-of-use carbon
A certified under-sink carbon filter can be one of the cheapest PFAS treatment paths when the exact model has a relevant claim.
RO cost
Countertop and under-sink RO usually cost a few hundred dollars and can address PFAS alongside many other dissolved contaminants.
Whole-house cost
Large carbon or ion-exchange systems require far more media and plumbing capacity. This can move equipment into the $1,000+ range before installation.
Replacement media matters
PFAS ownership cost should include cartridge or media replacement, not only the initial system.