How to Choose the Best Type of Water Filter

Annie Sisk
Written by Annie Sisk
Updated April 22, 2022
A kid filling a glass with tap water
Photo: yamasan / iStock / Getty Images Plus / Getty Images

Some filters get down to the nitty-gritty, while others keep it surface level 

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Lead in a home’s drinking water is a huge concern, especially for parents of young children and for owners of homes built before 1978. Tap water often contains contaminants that don’t change its color, smell, or taste—you can only detect them through water testing

To ensure your family enjoys clean, clear water, you may be thinking about buying a water filter for your home. However, given all the different brands, varieties, and water filtration methods, it can be challenging to pick the right one. Use this guide to sort out your options and make the best choice for you and your family. 

What Kind of Water Filter Do I Need?

Water filters can solve the problem of contaminants in your home’s water, but how do you choose the right water filter for your needs? To pick the right system for your home’s needs, think first about your ultimate goal. Do you want to remove contaminants from your drinking and cooking water? Or do you want to purify all the water flowing into your home for drinking, cleaning, and bathing purposes?

To find out what kind of method best suits your needs, start by testing the water via your home’s faucets, both inside and out. Also, consider the ease of installing and removing your system’s components, especially if you rent your home or apartment. Remember that whole-house systems typically require professional installation, so figure that into your budget and cost estimates before deciding. 

Common Causes of Water Contaminants

Contaminants in your home’s water supply can come from several different sources. However, some circumstances increase your chances of contaminated water:

  1. If you live close to a manufacturing plant, wastewater treatment plant, mine or quarry, large-scale agricultural or livestock farming operation, or nuclear facility

  2. If your water comes from a municipal source or a well 

  3. The age and condition of your plumbing system and fixtures

  4. Other external issues such as leaky septic tanks or heavy storm runoff 

6 Types of Water Filters for the Cleanest Water

1. Whole-House Filtration Systems

Best for: Purifying all water

Before you start considering specific kinds of water filters and decontamination devices, consider how much water flowing into and around your home needs to be filtered. 

Whole-house water filtration systems filter every ounce of water you use, whether for drinking, bathing, toilet flushing, or even watering your lawn. For some, this provides more filtration than you’ll ever need, but for others, it may be worth the cost, depending on the state of your water quality.

2. In-Line Systems

Best for: Removing harmful contaminants from drinking and cooking water

On the other hand, in-line systems are best if you only need to filter the water you drink and cook with. These systems are installed further along your home’s water system to filter the water coming from specific faucets and water outlets.  You can also choose point-of-use filters that attach directly to the faucet or stand-alone filters, such as pitchers and mobile reservoirs that you can keep in the refrigerator, to ensure cold, clean drinking water around the clock. 

3. Reverse Osmosis Filtration

Close-up of woman’s hand holding a glass under the tap
Photo: vitapix / E+ / Getty Images

Best for: Removing potentially dangerous toxins and contaminants

The reverse osmosis filter uses a three-stage filtration process to remove many kinds of contaminants: 

  1. A sedimentary prefilter: Removes silt, sand, and other larger particulates 

  2. A carbon filter: Removes tiny bits of organic matter that can impact how your water tastes and smells 

  3. A semipermeable membrane: Removes chemical contaminants, such as pesticides, bleach, salts, metals, nitrogen, bacterial toxins, and medications 

There’s an additional filtration stage in some systems that catch and remove any particulates or contaminants that slipped by earlier stages. 

While these filters catch contaminants, they don’t remove microorganisms like viruses and bacteria. Many municipal water sources use chemical disinfecting processes (like chlorination) to attack these toxins, but private wells and untreated water from natural sources can be more susceptible to disease-causing microbes. 

4. Ultraviolet Light

Best for: Removing bacteria and viruses

Ultraviolet light systems do what reverse osmosis filters can’t: kill the microorganisms in your water to prevent disease transmission due to viral or bacterial infection. UV light treatment can eliminate almost 100% of the microbes that chlorine treatment doesn’t get to first. 

However, UV systems on their own don’t do much to remove sedimentary and chemical particulates the way RO and absorption filters do (more on that below). As a result, many homeowners use UV light in combination with one of the other filtration methods for best results. 

5. Carbon and Activated Charcoal Filters 

Best for: Removing chlorine, chloroform, and other agricultural chemicals

Absorption water filters use carbon and activated charcoal to physically trap or capture contaminants and separate them from the water that flows into your home. 

Charcoal alone isn’t great at attracting and binding potential water contaminants, but when activated by oxygen, its binding capacity increases. Carbon and activated charcoal filters may not filter out quite as many contaminants as reverse osmosis, but they’re both effective enough to be dependable choices. They’re particularly cost-effective if your goal is to make your drinking water taste and smell better. 

6. Mechanical Filters

Best for: Removing physical particles 

In this case, “mechanical” doesn’t refer to a machine but the method behind the system. Most often employed as a preliminary filtration system, water flows through a mechanical filter and traps material between nylon floss, synthetic foam, or in pads. This acts as a sieve to capture the largest particles as the water reaches the filter. To capture the remaining smallest particles, mechanical filters employ gradually changing filters in increasingly more restrictive sizes, usually conveyed by micron rating. 

The smaller the micron rating, the smaller the particulates and contaminants it can remove from your water. For example, a 5 micron rating means the filter efficiently removes most larger particles, while a 0.5 micron rating means it can remove much smaller contaminants you’d need a microscope to see. 

No matter what type of water filtration system you choose for your home, you’ll probably want to hire a professional plumber to install it. 

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