To improve water’s clarity and taste throughout a building, consider installing a robust point-of-use filtration system that fits neatly in a cabinet under the sink. There are lots of options available that vary in filtering ability, and each of them will save residents time and effort each time they go to the sink for a glass of water.


Better Filtration

Under-sink systems can consist of a single filter, but many rely on a combination of filters to remove specific minerals and additives. Some systems combine carbon-type filters with reverse osmosis (RO) technology. In an RO system, the water is forced through a semi-permeable membrane that can remove contaminants down to the bacteria level. Because RO systems take time to work, components include a four- or five-gallon storage tank so that fresh water always is available.

Some under-sink systems include an ultraviolet (UV) light chamber. The UV light does not filter anything, but can zap bacteria to further sanitize the water.

As with any water filtration system, it should meet the standards of NSF International or the Water Quality Association. That is the only way you can verify the manufacturer's claims.



Installing an under-sink filter involves tapping into the cold water line and then running the water through the system and up to a dedicated faucet in the sink deck. Some products tie into the water line so that the existing faucet dispenses the filtered water. The connections are either compression fittings that you attach using a wrench or quick-connect fittings. Most systems do not require soldering so installation is easily manageable.

The filters need to be changed periodically, usually on a 6- or 12-month schedule. RO membranes last about two to three years.

For any building, an under-sink filtration system is a reliable way to obtain clear and better-tasting drinking water. To choose the best system for your needs, send off a sample of the building’s water to have it tested (especially if the water is sourced from a well). The test results will help you make the right purchase.


Author bio: Fran Donegan writes for The Home Depot on home improvement topics, including water filtration systems and planning. Fran also is a longtime DIY writer and the author of several DIY books. You can review a large variety of water dispensers and filters on the here. This article is editorial content that has been contributed to our site at our request, and is published for the benefit of our readers. We have not been compensated for its placement.