For most households, reverse osmosis is the most practical fluoride-treatment category. Verify an exact fluoride-reduction claim under NSF/ANSI 58 or equivalent model-specific testing before buying.
Best overall category: reverse osmosis
RO is the strongest mainstream household option because the membrane can reduce fluoride along with many other dissolved contaminants. Countertop RO is especially useful for renters; under-sink RO is better for permanent high-volume use.
Waterdrop, Frizzlife, RKIN and JIMMY all give WaterVerdicts available RO paths, but the exact model evidence should control the recommendation.
Best no-install option: countertop RO
Countertop systems avoid drilling and drain connections. That makes them attractive for apartments, offices and temporary housing.
The tradeoffs are countertop space, electricity and proprietary replacement cartridges.
What not to buy for fluoride alone
Basic activated-carbon pitchers and shower filters should not be assumed to reduce fluoride. Carbon is excellent for chlorine and many organics, but fluoride needs a different treatment mechanism.
How to verify performance
NSF/ANSI 58 includes an optional fluoride-reduction claim. Confirm the exact finished system, not merely that a manufacturer mentions Standard 58 somewhere in its marketing.