What Is Water Filtration and How Does It Work?

WHAT IS WATER FILTRATION?

• Benefits of In-Home Water Filtration 

WATER TREATMENT OPTIONS FOR THE HOME

• Drinking Water Point of Use (PoU) Filtration Systems
  • Activated Carbon Water Filtration
  • Reverse Osmosis Water Filtration (RO)
• Point of Use (PoU) Water Filtration Products
• Whole-Home Water Filtration Systems

WHICH WATER FILTRATION OPTION IS RIGHT FOR YOU? 

• Water Filtration Considerations to Keep in Mind
• Evaluating Water Filtration Products 
  • Water Filtration Industry Standards & Independent Lab Testing
  • Water Filtration Product Performance & Maintenance Specifications

Are you worried about the tap water in your home? If so, you’re not alone. More than half of Americans are concerned about the water they use for drinking and bathing.   Many people have turned to bottled water as an alternative. Unfortunately, bottled water isn’t a perfect solution. In addition to being a pricey option, plastic bottles are a known environmental problem and may contain microplastics, yet another growing concern.

Don’t worry, though, you have options. This article covers what water filtration is and the basics about water filtration, so you have the information you need to positively impact the quality of water in your home. If you want to learn more about water quality in general, check out Understanding Water Quality. 

Water filtration is the process of removing contaminants from your water. Commonly removed contaminants include: particles (e.g., dirt, rust and sand); chemicals and other substances that impact human health or aesthetics, such as the taste and smell of the water; and pathogens like viruses, bacteria and parasites.

Benefits of In-Home Water Filtration 

In addition to limiting use of bottled water, filtering your water for drinking; making coffee, tea and other beverages; rinsing fruits and vegetables; and cooking is a great way to reduce contaminants beyond EPA standards. You can also reduce emerging contaminants that aren’t even regulated yet and improve the taste and smell of your water.

The benefits of filtered water extend beyond the kitchen. Some chemicals in our water, such as chlorine, can cause dry skin and hair, but filtering water for showering or bathing can remove those contaminants.

Keep in mind, however, that multiple filtration options are available, and they may not remove the same contaminants. Always review the manufacturer’s information and look for third-party certifications (see Evaluating Filtration Products) to find out what the filtration system removes from your water. 
 

Nearly half of Americans filter their drinking water at home.   Some systems, often called Point of Use systems, treat the water only where you need it—at the kitchen sink, refrigerator or shower, for example. Point of Entry filtration options are whole-house water filtration systems that treat all of the water coming into your home before it’s sent to any plumbing fixtures or the hot water heater. Let’s take a closer look at these filtration solutions.

Drinking Water Point of Use (PoU) Filtration Systems 

The two most common PoU filtration options for the home are activated carbon filters and reverse osmosis filtration systems.

Activated carbon is a highly porous material commonly made of coal, coconut shells or wood. Activated carbon water filters use chemical absorption to remove contaminants and impurities, such as chlorine and sediment.

Reverse osmosis (RO) systems include semipermeable membranes that water is pushed through to remove harmful chemicals, pathogens and minerals from the water. Considered the gold standard in filtration, most Reverse osmosis water filtration systems use more than one type of water filtration to remove sediment and reduce contaminants (e.g., RO plus activated carbon) and feature multiple stages of water filtration.

Some RO systems also offer remineralization cartridges, which add good-for-you minerals like electrolytes, calcium and magnesium to enhance the taste and pH of your water. Check out our Delta® Clarifi™ Tankless RO System to learn more.

Other in-home water filtration and treatment options include:

• Distillation units, which boil water and condense the steam to produce purified water
• Ultraviolet (UV) water filters that kill bacteria and viruses with UV light
• Ceramic water filters with small pores that block contaminants from flowing through 
• Ion-exchange water filters, which swap ions in the water with ions on beads in the filter to remove minerals and contaminants

Point of Use (PoU) Water Filtration Products 

If you’re looking for a PoU drinking water filter, you have a variety of options to choose from.

Pitchers are an affordable and easy-to-use way to improve your tap water by reducing substances like chlorine and lead. 

• Countertop systems usually provide more capacity and are available with different water filtration options, such as activated carbon, RO and ceramic. 
• Faucet attachments connect directly to your faucet, typically feature an activated carbon water filter and/or ion-exchange water filter, and often come with an on/off switch, so you can filter water only when needed. 
• Water dispensers, aka water coolers, frequently use bottled water, but bottleless models with filtration (e.g., UV or activated carbon) are also available. 
• Under-counter water filtration systems can be paired with your primary faucet or a beverage faucet to dispense filtered water at the sink. These systems are available with different filtration solutions, such as RO or activated carbon.
• Refrigerators are available with an integrated water filter to improve your water.
• Shower Filters: When people think about water filtration, drinking water is usually top of mind. But the quality of water can also impact your skin and hair (see Understanding Water Quality). Shower water filters attach to your shower head to remove contaminants, like chlorine, that may cause dry skin and hair. Find out more at Delta® Clarifi™ Shower Filter Attachment.

Whole-Home Water Filtration Systems 

Point of Entry (PoE) systems that filter all of the water coming into the home are installed near the incoming water supply. Although these water filtration systems are more complex to install and have a higher upfront cost, they’re capable of removing a wide range of water contaminants and conveniently supply filtered water wherever you want it.

Whole-house water systems may feature one or more water filtration type, including activated carbon, RO, UV and ion-exchange. When researching these water filtration systems, you’ll find these options as well:

• Water softeners are ion-exchange water filtration systems that replace minerals that cause hard water, including calcium and magnesium, with sodium. 
• Salt-free water conditioners typically use potassium to crystalize the minerals that cause hard water, so the scale is less likely to build up on your fixtures.
   

To find the right water filtration system for your home, start by figuring out what’s important to you and your family.

Water Filtration Considerations to Keep in Mind 

Water Quality: Are you worried about potentially harmful health-related contaminants? Do you have concerns about how your water tastes and/or smells? Is filtered water only needed for drinking and cooking, or do you want cleaner water for showering/bathing as well? Answers to these questions will help you determine what type of water filtration product you need and where to install it.

Lifestyle: Would you prefer a water filtration system that’s hidden from view (e.g., installed under the counter), or is it okay to be visible (e.g., a countertop system)? How often are you willing to change the water filter? How many people will be using filtered water? Thinking through these issues will help narrow your water filtration options and determine what water filtration capacity you need.

Timing and Budget: How quickly do you need a water filtration solution, and how much are you willing and able to spend? Some filtered water solutions are relatively quick, easy and inexpensive to implement, while others (e.g., whole-house water filtration systems) require more planning and investment. In addition to upfront product and installation costs, be sure to consider the cost, frequency and ease of water filter replacement as well as any bottled water savings.

Evaluating Water Filtration Products 

There are so many water filtration products on the market, it can be overwhelming. To help evaluate your options, look for third-party certification of industry standards and compare key water filtration product specifications.

Water Filtration Industry Standards & Independent Lab Testing 

Water Filtration Industry standards are developed to ensure products meet specific performance requirements, and independent labs test products to confirm they meet those standards. Why is that important? It provides independent, third-party verification that the water filtration product is effective, so you can have confidence in your purchase.

For water filtration products, the National Sanitation Foundation (NSF), a global leader in developing standards that help protect human health, sets the testing standards. NSF, the Water Quality Association (WQA) and The International Association of Plumbing & Mechanical Officials (IAPMO) are independent organizations that test and certify filtration products to NSF standards.

Water filtration products that are tested and meet NSF standards are certified to reduce various types of contaminants, including:

• NSF-42: Non-health related contaminants, including aesthetic impurities that impact taste and/or odor (e.g., chlorine)
• NSF-53: Contaminants that may impact health, including volatile organic chemicals (VOCs) and PFAS (commonly known as “forever chemicals”)
• NSF-58: Contaminants that are reduced through reverse osmosis, including total dissolved solids (TDS) such as calcium and magnesium, and other optional contaminants (e.g., various chemicals and cyst) 
• NSF-372: Lead content
• NSF-401: Emerging contaminants that aren’t yet regulated by the EPA (e.g., BPA, DEET and ibuprofen)
• NSF-P231: Contaminants removed by microbiological water purifiers, including bacteria, virus and cyst

Water filtration product specifications and/or performance data sheets should include details about which NSF standards the product has been tested and certified to meet. 

As you research water filtration products, you may also find references to the IAPMO R&T Water Quality Platinum Seal and WQA Gold Seal from the Water Quality Association. These are third-party certifications from accredited plumbing industry associations, indicating that the product has been independently tested to remove certain contaminants.

Water Filtration Product Performance & Maintenance Specifications 

Water filtration product specifications help determine if a model will meet your needs and let you make direct comparisons between different water filtration solutions. A few attributes you may want to consider include:

• Filtered Water Flow Rate: How long it takes to dispense filter water, typically measured in gallons per minute (gpm)
• Filtered Water Storage: The amount of purified water the system can hold (e.g., a pitcher will hold several cups of filtered water, whereas a tankless under counter RO system will provide an unlimited supply of filtered water) 
• Water Filter Capacity: The amount of water the system can filter before it needs to be replaced
• Water Filter Life: How long the filter will typically last before it needs to be replaced

Depending on your needs and preferences, you may opt for a single water filtration system or a combination of different filtered water options to deliver the desired water quality (e.g., a tankless under sink Reverse Osmosis water filtration system in the kitchen and a shower filter in the primary bathroom). No matter what you choose, you’ll be taking a step toward having cleaner water for you and your family every day.