How to Choose a Water Filter

Another type of water filter is faucet mounted. These are typically easy to install (they screw right onto the faucet head), and some feature a filter directly in the unit attached to the faucet while others have tubing that connects to an external block that sits on your countertop. By connecting to your faucet, they allow seamless access to filtered water straight from the tap. However, these systems may not work with all faucets and some can slow down your flow rate.

When it comes to performance, you’ll likely find many differences, especially if you’re comparing faucet mounted filters with an internal filter (in the unit attached to the faucet) compared to systems that connect to an external block. Systems that do all the filtering internally may offer lesser performance due to sacrifices that favor the form factor, while units that filter through an external block may have better performance because they can include multiple stages of filtration like activated carbon and ion-exchange.

In general, faucet mounted water filters can help with bad odors and taste as well as remove some contaminants such as lead and chlorine. Depending on the certification, some can effectively remove sediment, chemicals, heavy metals, pesticides, and more.

Prices can range from $15 to $80 which put them around the same range as pitchers, but with potentially better performance and greater convenience since you don’t need to worry about refills. Filter lifespan is similar to pitchers, with most systems needing a replacement every two to three months.

Countertop filters are the most convenient option for renters or for those unable to make plumbing modifications because they are portable and don’t require permanent installation. Some countertop filters overlap with faucet mounted filters, if you consider the external block to make it more of a countertop system. However, other countertop water filters can be completely away from the kitchen faucet. For example, the Clean Water Machine can be plugged in anywhere with an outlet to accommodate the kitchen space you have available.

There’s a wide variety of countertop water filters, including those with carbon filtration, ion - exchange, ultraviolet light, sub-micron mechanical filtration, or a combination of these. And each type of filtration media helps with removing different contaminants. Some countertop filters on the market can filter up to 99% of 78 contaminants. 

Costs range from $80 to more than $1,000, but you likely won’t have to worry about additional installation costs with an easy to DIY process. When it comes to replacements, some filters feature multiple stages of filtration but you can typically expect them to last between 6-12 months.

Before making a purchase, you should always check a water filter's packaging for a stamp or seal confirming which contaminants the filter is certified to remove. It's important to ensure a water filtration system is tested and certified to NSF Standards by an unbiased third-party testing group like the Water Quality Association (WQA), the International Association of Plumbing and Mechanical Officials (IAPMO). 

When looking at different water filters and certifications, various systems will have different testing standard numbers. These numbers indicate what the system was tested for, according to the NSF Standards. Here are a few NSF standards to be aware of.

• Standard 42: Reduces aesthetic impurities like chloramine, chlorine, taste, and odor.
• Standard 53: Reduces contaminants with health effects. These contaminants include asbestos, cysts, PFOA/PFOS, VOCs, and more.
• Standard 55: Sterilizes bacteria, viruses, and cysts. This standard is associated with ultraviolet treatment systems that use a UV lamp.
• Standard 58: A reverse osmosis only standard that incorporates filtration through a semi-permeable membrane. Reduces arsenic, fluoride, TDS, and more.
• Standard 401: Removes emerging compounds/incidental contaminants like prescription drugs, over-the-counter medications, herbicides and pesticides, as well as chemical compounds like BPA.  
• Standard P473: Reduces perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) — chemicals used to make non-stick cookware, fire retardant, and more. In 2019, NSF combined Standard P473 into NSF Standard 53, so you may not see it listed for new filters.
• Standard P231: This reduces microbial contaminants like bacteria and viruses.
• Standard 372: This minimizes lead contamination, consistent with the United States Safe Drinking Water Act (SDWA).

Choosing the best water filter ultimately comes down to what specific contaminants need to be filtered from your water, where you want to install your filter (or perhaps you don't want to install anything), and your budget. Aquasana has a wide range of water filters whether you need under sink, countertop, or whole house systems. All of our water filtration systems are tested and certified through NSF or through WQA and IAPMO to meet NSF standards. 

If contaminant removal is your top priority, we recommend the Aquasana SmartFlow® Reverse Osmosis filter, which removes up to 99.99% of 90 contaminants including fluoride, arsenic, chlorine, and lead. It also features a remineralizer so you'll retain healthy minerals that are beneficial to your body and contribute to a better taste in the water you use.

If you're still unsure which water filter is best for you, contact us and we'll be happy to help.