Benefits of an Under-Sink Water Purifier

Under-sink water purifiers eliminate sediment particles, chlorine odors and chemicals, and more for bottled-worthy drinking. Options that include a reverse osmosis membrane reduce a broader set of contaminants, including fluoride and TDS.


The iSpring 6-Stage Reverse Osmosis System is a top pick that softens hard water and restores healthy minerals to the water for better taste. It removes 77 contaminants, including heavy metals, and reduces up to 98 percent of lead and chlorine.

1. Less Empty Bottles

If you use a home water filtration system, you’ll spend far less on bottled water and will help reduce the amount of empty bottles that clutter the environment. In addition, these filters are known for their ability to give filtered water a much-needed boost in flavor.

Under-sink water purifiers are one of the best ways to snag better tasting water without paying an arm and a leg for it. These point-of-use filters install right at your sink and connect to your water line, so you can filter your tap water before it hits the refrigerator or faucet. They also take up far less space than countertop or pitcher water filters.

Traditional under-sink systems divert your cold-water line to the filtration unit through a flexible plastic tube. From there, filtered water is delivered to you via your sink’s dedicated filter tap or through a separate, dedicated faucet mounted on top of the sink. Because the filtration process removes some healthy minerals, many under-sink models come with an alkaline filter that helps to add back in these nutrients.

When choosing an under-sink water filtration system, consider how often you’ll need to change the filters. Single-stage systems typically need to be changed after about six months or 500 to 700 gallons, while those that use reverse osmosis can last up to two years before the filters lose efficiency.

2. Less Waste

Many water filtration systems produce waste in the form of discarded filters and spent water. This waste pollutes the environment and can also lead to bacterial contamination. By investing in an under-sink water filter, you can reduce the amount of waste produced by your family.

Under-sink water filters typically produce less waste than portable filters and can eliminate the need for reusable bottles altogether. This is a big deal since empty plastic bottles contribute to pollution and landfill waste.

Most under-sink water filters rely on reverse osmosis to remove impurities from the water. The process works by separating a diluted solution into a concentrated one through a semipermeable membrane. The diluted solution spontaneously moves into the concentrated side through the membrane, forcing the concentrations to equalize. This type of filtration system is effective at removing contaminants, such as chlorine, chlorine treatment byproducts, arsenic, and lead, while retaining healthy minerals that improve the taste and flavor of drinking water.

Some under-sink water filters can add an extra step of filtration, which is known as specialty filtration. This can include options such as carbon filtration, water ionization, or UV filtration. These options are effective at reducing certain types of contaminants, but they may require more maintenance and upkeep than other filtering methods.

Under-sink water filtration systems can help you to enjoy cleaner, better-tasting drinking water with little or no maintenance required. These systems are installed under your sink, which can free up storage space under the kitchen counter that would otherwise be used for pitchers of water.

3. Better Taste

With under-sink filters, you can enjoy water straight from your tap that’s been filtered to get rid of chemicals, odors, and other contaminants. They’re typically more advanced than countertop filters, making them the preferred option for those who want to ensure they’re drinking pristine water every time they turn on the faucet.

In addition to removing bad odors and chlorine, many under-sink systems also add back in healthy minerals and boost the pH level of your tap water for a fresher taste. These are great for homeowners who spend a lot on bottled water or have hard well water that requires additional filtration to soften.

Under-sink water filter systems can be connected to your existing faucet or a dedicated one that is included with the unit. Those that work with your existing faucet will usually have a flexible plastic tube that diverts the water to the filter before it goes to your sink’s cold-water supply.

This allows the filter to keep the water at a constant temperature without mixing with cold, unfiltered water from your sink. However, it’s important to note that most under-sink water filters don’t chill the water they produce, meaning you’ll have to store it in the fridge or add ice cubes for chilled drinks. This is especially important if you’re using the system to drink on the go or for cooking purposes.

4. Environmentally Friendly

Under-sink water purifiers divert filtered water into your sink through a flexible plastic tube that connects to the cold water line under the kitchen sink. The water then flows through a dedicated faucet that sits on the top of your sink. This means that the filtered water never mixes with unfiltered water, so your family gets only clean, healthy water on demand.

Depending on the contaminants you want to remove, under-sink filters offer various technologies, configurations and sizes. Some popular options include reverse osmosis and carbon filtration. It’s important to do some research to find a system that is certified by third parties and has the capability to remove your most-wanted contaminants, such as fluoride, chlorine, arsenic, uranium, microplastics and E. coli.

Most under-sink water filter systems have two or three different filtration stages, including a sediment filter that traps dust, dirt and silt, a pre-carbon filter that reduces chlorine and odor and an RO membrane that removes contaminates like heavy metals and PFOAs. Many of the best under-sink filters also have specialty filtration capabilities, such as an alkaline boost cartridge or Culligan’s Total Defense that addresses lead and mercury.

The filter cartridges used by under-sink water filtration systems need to be replaced on a regular basis. The frequency will depend on the type of contaminant your water is exposed to and the level of usage. Some under-sink filters have displays that let you know it’s time to change the cartridges, while others require that you check your water quality test results to determine when it’s necessary.