Water filter marketing focuses on purchase price, but the true cost of PFAS protection is best understood on a per-gallon basis over the filter’s usable life. This analysis often reverses the intuitive ranking of options by upfront cost.
Pitcher Filters
Certified PFAS-reducing pitcher filters typically cost $30 to $60 for the pitcher and $20 to $40 per replacement filter rated for 40 to 100 gallons. At 80 gallons per filter and $30 per replacement, the filter cost alone is $0.38 per gallon — making pitchers among the most expensive options on a per-gallon basis despite their low upfront cost. High-volume households amplify this cost significantly.
Under-Sink Carbon Filters
Under-sink carbon block systems cost $100 to $400 installed, with replacement filters at $30 to $80 rated for 500 to 1,000 gallons. At 750 gallons per filter and $50 replacement cost, the ongoing cost is $0.07 per gallon — substantially lower than pitchers. Amortizing the upfront system cost over 5 years of service brings total cost to approximately $0.10 to $0.12 per gallon.
Under-Sink Reverse Osmosis
RO systems cost $200 to $600 installed, with annual filter and periodic membrane replacement costs of $60 to $150 per year. For a family consuming 2 gallons of filtered water daily (730 gallons/year), ongoing filter costs run $0.08 to $0.21 per gallon. Over a 5-year system life with amortized hardware cost, total RO cost typically falls in the $0.15 to $0.30 per gallon range — higher than under-sink carbon but substantially lower than pitchers for high-volume users, with superior PFAS removal performance.