In This Buyer’s Guide:
- Why should you buy an undersink water filter system?
- Which contaminants do undersink water filter systems remove?
- How to install an undersink water filter
- Which undersink filter is right for you?
Why should you buy an undersink water filter system?
If you live in a large household and need to filter large amounts of water for cooking and drinking, an undersink filter system provides a less costly alternative to reverse osmosis filtration, both in terms of water waste and financial expense. Installation does require some changes to your household plumbing, but in many cases, the filters last longer and may be more efficient at filtering out contaminants than water filter pitchers, countertop water filters or refrigerator water filters. Most undersink filters also come with a separate water dispenser that allows you to choose between filtered and unfiltered water. Once installed, changing the filter(s) is as easy as removing the canister and inserting the replacement cartridge. Moreover, since these filters are hidden underneath the kitchen sink, they will not take up space inside your refrigerator or on your countertop. They come in a variety of shapes and sizes to suit the space under your sink, as well as a wide range of prices to suit your financial needs.
Which contaminants do undersink water filter systems remove?
Most undersink filters use an activated carbon filter media that reduces the bad taste associated with chlorine taste and odor. Some also have pre-filters that remove sediment, dirt, sand, silt, rust and limescale. More advanced undersink water filters may also remove other contaminants as small as 0.5 microns, including: lead, microbial cysts (cryptosporidium and giardia), algae, mercury, pesticides, herbicides and volatile organic compounds (VOC’s). It is important to test your water before buying an undersink filter to determine what contaminants need to be removed. This can be done through a water testing laboratory or at home with a water test kit. For more information, see our article, “How to Test Your Drinking Water.”
How to install an undersink water filter
Always follow all instructions contained in the package when installing your water filter system. The basic installation process is as follows:
1. Many undersink filter systems come with a separate water dispenser, allowing you to choose between filtered or unfiltered water for various uses. Mount the faucet dispenser that comes with your installation kit to the top of the sink. Most are designed to fit into the extra hole where the sprayer is usually located, but if this is already occupied and you want to continue to keep the sprayer where it is, you’ll have to drill another hole. Follow the manufacturer’s instructions for the location and size of the hole, and only drill into stainless steel or porcelain cast-iron sinks. If your sink is all-porcelain, drill through the countertop instead.
2. Shut off the water supply under the sink. Use an adjustable wrench to disconnect and remove the tubing that connects the water faucet and the supply valve.
3. Install the filter in the space between the cold water supply and the faucet, underneath the sink where the rigid water supply line was removed. An undersink filter kit usually includes flexible supply lines. Connect one from the water supply to the filter inlet, and connect the other from the filter outlet to the faucet tubing, making sure all fittings are sealed water-tight to prevent leaks.
4. Mount the canister to the back wall of the cabinet underneath the kitchen sink. Make sure it is mounted high enough to allow enough space for the removal of the canister body when changing the filter.
5. Turn on the water supply. Check the system and its fittings for any sign of leaking, and adjust the fittings if necessary.
Which undersink filter is right for you?
The type of undersink water filter you need depends on what’s in your water supply and what you want removed. The most basic filters remove the bad taste and odor associated with chemicals like chlorine, while more advanced filters will remove more. Here are some of the filters we carry along with their features and specifications, listed according to our opinion of where they rank in terms of overall performance. Please click on the links for more detailed product descriptions, and/or to purchase the filter.
Good
Culligan US-EZ-4 Undersink Water Filter System
This system is ranked premium by Culligan standards. It reduces many contaminants including the bad taste and odor of chlorine, class I particulates, sediment, turbidity, lead, mercury, VOC’s, MTBE and cysts. Unlike the Culligan US-EZ-1 and US-EZ-3, the Culligan US-EZ-4 will also filter chloramines from your water, which many municipal water treatment plants are beginning to use as disinfectant. The system includes a lead-free faucet with a built-in filter life indicator that lets you know when to change your filter. Replacing the filters involves a simple twist of the wrist and should be done every 500 gallons or six months. .
OmniFilter CBF3 Undersink Water Filter System
This filter system reduces many contaminants larger than 0.5 microns, including: rust, sediment, asbestos, chlorine, chloramine, lead, cysts, mercury, pesticides, herbicides and VOC’s, from your drinking water. It is easy to install and allows for easy filter replacement. Filters should be changed every 550 gallons or every six months.
Aqua-Pure AP200 Compact Undersink Filter System
This compact filter system fits right underneath your kitchen sink and comes with a mounting bracket for easy installation. The premium dual-action cartridge reduces the basics – rust, along with chlorine taste and odor – leaving you with fresh-tasting water for drinking and cooking. This is perfect for a household that needs the type of long-term, basic filtration that water pitcher filters can’t provide.
Better
Pentek 1500 Monitored Undersink Water Filter System
The Pentek US-1500 Monitored Undersink Water Filtration System efficiently reduces dissolved lead, cysts, chlorine taste and odor, chemicals, sediment, particulates, mercury, VOC’s, pesticides and herbicides. This system also comes with an electronic monitor that lets you know when it’s time to replace the filter. Filters should be changed once per year, or every 1,000 gallons.
Aqua-Pure AP Easy Complete Drinking Water System
The AP Easy Complete Undersink Water Filter System comes with a lead-free faucet and effectively reduces lead, chlorine taste and odor, cysts, sediment, scale and VOC’s. The filter cartridge should be changed every 500 gallons.
Doulton HIP/DIY UltraCarb Undersink Filter System
The Doulton UltraCarb system comes with a chrome faucet and uses a ceramic filter candle for the reduction of cysts, chlorine, class I particulates, turbidity and lead. Depending on water quality and usage, the filter should be changed every six months to one year.
Best
Everpure H-300 Undersink Water Filtration System
This powerful, commercial grade filter system is ideal for any home or business. It uses an advanced Everpure Micro-Pure Quick Change Filter Cartridge that removes a long list of contaminants, including: lead, mold, cysts, algae, rust, sand, silt, asbestos, sediment, dirt, limescale, particulates, oxidized iron, oxidized sulfides, oxidized manganese, chlorine taste and odor, chloramine taste and odor, VOC’s, THM’s and any other particles larger than 0.5 microns. It also features Bacteriostatic control to stop the growth of bacteria inside the cartridge, which prevents premature clogging. The filter has a life of about 300 gallons and should be changed when you notice a significant reduction in water flow from the system. This water filter system does not come with a faucet; however a compatible faucet, such as the stainless steel Everpure Exubera Water Faucet may be purchased separately.
AquaPure Undersink Water Filter System AP-DWS1000
This water filter system filters lead, sediment, rust, cysts, VOC’s and MTBE. It comes with a lead-free faucet and features a built-in monitoring device that shuts off water to remind you when it’s time to change the filter. The quick change filter cartridges should be replaced every six months or 625 gallons.
Featured
Watts 3-Stage Undersink Water Filter System WQCFU-T-11KIT
The Watts 3-Stage Undersink Water Filter System filters water in 3 stages for the effective reduction of many contaminants, including: chlorine taste and odor, class IV particulates, sediment, dirt, silt, sand, THM’s, limescale, rust, dissolved solids, lead, chemicals, VOC’s, cysts, herbicides, pesticides, insecticides and more. It is a less-expensive alternative to the Watts Kwik Change Reverse Osmosis system, using color-coded quick change filters for easy replacement. It also uses 100 percent of the water it takes in, leaving no wastewater, unlike the reverse osmosis system.
Pentek 3-Stage Arsenic Reduction Undersink Water Filter System AS-301E
The Pentek 3-Stage system is specifically designed to filter arsenic III and V, along with iron, manganese, hydrogen sulfide and chlorine taste and odor. Filters should be changed every 1,000 gallons or at least once per year.