Under-Sink Water Filters: Types, Costs, and Installation
Complete guide to point-of-use water filtration for drinking and cooking.
Why under-sink is popular
An under-sink filter treats water at the kitchen tap only, where you actually drink and cook. This means smaller, more affordable filters can use more intensive technology (like RO) that would be impractical or expensive at whole-house scale. Most under-sink systems include a dedicated filtered water faucet.
Types
Carbon block ($50-150): Removes chlorine, taste, odor, some VOCs. Does NOT remove TDS, fluoride, or most heavy metals. Reverse osmosis ($150-400): Removes 95%+ of dissolved solids including lead, PFAS, arsenic, fluoride, nitrate. Produces waste water. Ultrafiltration ($100-250): Removes bacteria and particles down to 0.01 micron. Does not remove dissolved contaminants.
Installation
Most under-sink systems are DIY-installable with basic tools. You need: space under the sink, a cold water connection (usually a saddle valve or tee fitting), and a drain connection for RO waste water. Professional installation runs $100-200 if you prefer.