Under-sink water filters save counter space, last a long time, and are cost-effective; however, they also have some disadvantages, so they may not be the right choice for everyone.
With an under-sink water filter, a plastic tube diverts water to the filters while another plastic tube delivers filtered water to a special faucet on top of the sink.
Under-sink water filters are convenient and offer targeted filtering at the point of use. In addition, you don't have anything extra on your counters, so you cut back on clutter.
Maintenance is also minimal, and the filtration system yields quality results. The average cost is from $100 to $300, and you can buy an installation kit for an extra $50 to $80.
On the flip side, the dispenser has a slower flow than most people would like. It's a smaller faucet and the pressure is less than ideal, but it is sufficient for drinking use.
It also has no method of refrigeration, so you’ll have to add ice, and it does take up space underneath your sink, which might matter for very small kitchens.