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Choosing Home Water Filters & Other Water Treatment Systems

Step 3: Consider how the filter fits your home, lifestyle, and budget.

Many different types of filters are available to consumers. Determining which type is most appropriate for you—or whether you need a filter at all—depends on what functions you want a filter to provide. No filter eliminates all contaminants, so understanding what filters do and do not do is important.

What does the filter remove?

Read the label to see if it is NSF-certified.  If it is, you can search NSF’s database to learn more about what a particular model is certified to protect you against. Labels on water filters also typically state the contaminants that are reduced, which can help to guide your choice. Be sure to read labels carefully yourself and verify the manufacturer’s claims with an independent source, as not all sales representatives will be familiar with your needs.

Keep in mind that most brands include many different types of filters. Sales people might be able to help you make an appropriate selection, but remember that they are sometimes paid to sell a particular brand. You should check claims and read the fine print on filter packaging for yourself and ensure that it will work for your purposes before purchasing.

Don’t assume that if the filter removes one contaminant, it also removes others. Filters that remove chemicals often do not effectively remove germs, and vice versa. Some water treatment devices that remove chemicals, such as reverse osmosis, ion exchange, or distillation systems, might also remove fluoride. Children who drink water with levels of fluoride <0.6 ppm might need a fluoride supplement. Check with your child’s pediatrician or dentist for specific recommendations.

How much does the system cost?

The prices of different filtration systems can vary widely, from simple systems that can cost under $20 to complex systems costing hundreds of dollars and requiring professional installation. In addition to the price of purchasing and installing the system, consider the cost, schedule, and ease of maintenance, such as changing filter cartridges. In order to continue to work properly, all water treatment systems require maintenance.

How much filtered water do you need?

Some filters are slow, while others can filter large amounts of water quickly. If you only need the filter for personal drinking water, you may not need a fast filter.

What kind of system do you need, and how does it fit into your home?

Filters commonly found in homes and stores include water filter pitchers, end-of-tap or faucet-mounted filters, faucet-integrated (built-in) filters, on-counter filters, under-sink filters, and whole-house treatment units. No filters or treatment systems are 100% effective in removing all contaminants from water, and you need to know what you want your filter to do before you go shopping (see Step 1). Not all filters of a particular type use the same technology, so you should read the label carefully.  

Water filter pitchers

Water filter pitchers are pitchers that are filled from the top and have built-in filters that water must pass through before being poured out for drinking or other use.

  • Pros: Inexpensive to purchase, no installation, easy to use
  • Cons: Vary by model and pore size, filters must be replaced regularly, slow filtering

Refrigerator filters

Many refrigerators have a built-in filter that supplies water through the door and supplies an automatic icemaker.

  • Pros: Come with many refrigerators, often improve water taste, may also filter water used for making ice, easy to use
  • Cons: Filters must be replaced regularly

Faucet-mounted filters

Faucet-mounted filtration systems attach to a standard faucet and can be switched on and off between filtered and unfiltered water flow.

  • Pros: Can easily switch between filtered and unfiltered water, relatively inexpensive
  • Cons: Do not work with all faucets, may slow water flow

Faucet-integrated (built-in) filters

Faucet-integrated filtration systems are faucets designed with built-in filters (instead of an attached filter, like a faucet-mounted system) and require installation.

  • Pros: Can easily switch between filtered and unfiltered water
  • Cons: Often expensive, require installation

On-counter filters

Faucet-integrated filtration systems are faucets designed with built-in filters (instead of an attached filter, like a faucet-mounted system) and require installation.

  • Pros: Can easily switch between filtered and unfiltered water
  • Cons: Often expensive, require installation

Under-sink filters

Under-sink filtration systems are installed under a sink and send water through a pipe to the filter’s own specially installed faucet.  

  • Pros: Filter large amounts of water, do not take up countertop space
  • Cons: Often expensive, may require modifications to plumbing

Whole-house water treatment

Whole-house water treatment devices treat all water entering the house, not just the water used for drinking. 

  • Pros: Treatment is applied to all water entering your home, which may be important for hard water and volatile organic compounds (VOCs)
  • Cons: Often expensive, may require modifications to plumbing, may require professional maintenance, filtering that removes chlorine might increase growth of germs in all the pipes in your house

Treatment devices

This table shows some benefits and limitations of a few popular home water treatment technologies. It does not include information on all filter types including many those that might remove germs via simple pore size filtration. Also see Technical Information on Home Water Treatment Technologies.

Treatment Devices
Treatment Device What it Does to Water Treatment Limitations
Activated Carbon Filter (includes mixed media that remove heavy metals)
  • Absorbs organic contaminants that acuse taste and odor problems.
  • Some designs remove chlorination byproducts
  • Some types remove cleaning solvents and pesticides
  • Is efficient in removing metals such as lead and copper
  • Does not remove nitrates, bacteria, or dissolved minerals
Ion Exchange Unit (with activated alumina)
  • Removes minerals, particularly calcium and magnesium that make water "hard"
  • Some designs remove radium and barium
  • Removes fluoride
If water has oxidized iron or iron bacteria, the ion-exchnage resin will become coated or clogged and lose its softening ability
Reverse Osmosis Unit (with carbon)
  • Removes nitrates, sodium, other dissolved inorganics and organic compounds
  • Removes foul tastes, smells or colors
  • May also reduce the level of some pesticides, dioxins, chloroform, and petrochemicals
Does not remove all inorganic and organic contaminants
Distillation Unit
  • Removes nitrates, bacteria, sodium, hardness, dissolved solids, most organic compounds, heavy metals, and radionucleides
  • Kills bacteria
  • Does not remove some volatile organic contaminants, certain pesticides, and volatile solvents
  • Bacteria may recolonize on the cooling coils during inactive periods

Source: EPA. Water on Tap: What You Need to Know

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