Under Sink vs. Countertop Water Filters

When making the switch to filtered drinking water, the choices can be overwhelming.

By: Maggie Pace

If the water from your kitchen faucet or refrigerator doesn’t taste great or has a funky smell, it may be time to upgrade your drinking water. When making the switch to filtered drinking water, the choices can be overwhelming. After all, there’s a lot to consider when doing your research. Lifestyle, kitchen layout, convenience, and more. When it comes to under sink and countertop water filters, both types of filters have their own advantages and disadvantages. In this article, we will explain the differences between the styles, including installation, functionality and contaminants that are filtered out, plus options for both so that feel confident in your ultimate choice.

under sink water filters

Under sink water filters are filters that are installed underneath your sink to filter your water for drinking, cooking, and more. Under sink filters are a very popular water treatment choice for homeowners and renters alike, since they are relatively easy to install and can be moved if needed. Let’s discuss the advantages and disadvantages when investing in an under sink water filter.


  1. Out of sight: Because under sink water filters are installed underneath your sink and in a cabinet, they are out of sight and off your countertop. If you’re limited on countertop space in your kitchen, under sink water filters are a great option. Additionally, they don’t take up any space in your refrigerator since the filters attach directly to your water lines, giving you immediate access to clean water.
  2. Faster water flow: Since under sink water filters are connected directly to your kitchen sink’s water line, you’re not having to refill a pitcher or a machine to get access to water. With a faster flow rate, you won’t have to wait for healthy water.
  3. Performance: Under sink water filters offer incredible filtration performance, which typically exceeds the level of filtration you’d get from standard countertop pitcher filters. Performance varies depending on the system you choose, but all of Aquasana’s under sink water filters reduce up to 99% of 77 contaminants. Our OptimH2O® Reverse Osmosis + Claryum® tackles a whopping 89 contaminants, including lead, fluoride, chlorine, and more.


  1. Installation: With four out of our five under sink water filters, you must install a dedicated faucet. Depending on your comfort level with household projects, all under sink filters can be a DIY project. If you’re not comfortable with disconnecting water lines underneath your sink or potentially drilling a hole in your sink or countertop, we recommend hiring a professional plumber. If you have a side/vegetable sprayer you don’t use, using that space is the perfect alternative to drilling a hole for the dedicated faucet. For more information on choosing the right water filtration when it comes to sprayers, check out our helpful article.
  2. Price: When choosing a water filtration system, you’ll likely notice a difference in price between under sink and countertop filters. Under sink systems usually offer more powerful filtration but come at a price that typically exceeds what you’d pay for a countertop filter. Carefully consider your filtration needs to determine which system is best for you.

Aquasana Under Sink Water Filters:

Our award-winning under sink filters remove up to 99% of 89 contaminants to instantly transform ordinary tap water into clean, healthy water.

If you want to filter your water from a dedicated faucet:

  1. OptimH2O® Reverse Osmosis + Claryum®: Maximum removal of 89 contaminants including fluoride and arsenic.
  2. Claryum® 3-Stage Max Flow: Removes up to 99% of 78 contaminants, with a super-fast water flow.
  3. Claryum® 3-Stage: Reduces 78 contaminants, plus includes a Pre-Filter to tackle sediment and rust.
  4. Claryum® 2-Stage: Reduces 78 contaminants for pristine, great-tasting water.

If you want to filter your water from your existing faucet:

Claryum® Direct Connect: Easy to install, fast-flowing filter that connects directly to your existing faucet to reduce 78 contaminants.

countertop water filters

If you’re not a fan of the taste or quality of your tap water, a countertop water filter is a great alternative to an under sink filter. Countertop filters require very little assembly or installation, and some are ready to go from the moment you unbox them. As the name implies, our countertop filters sit on your countertop and efficiently deliver clean water. Compared to under sink water filters, there are some advantages and disadvantages for these filters.


  1. Installation: Countertop water filters typically have a much simpler installation process compared to under sink filters. In fact, Aqausana’s countertop filters require very little to no installation, and no plumbing is required. Our Clean Water Machine doesn’t even need to be connected to your kitchen faucet. Simply take the unit out of the box, plug it into an outlet, and fill with water!
  2. Portability: Because countertop filters don’t require any permanent installation, you can take them with you anywhere. For those who love to travel, pack your filter and use it in your RV, hotel room, or anywhere else you have access to electricity.
  3. Price: As we mentioned earlier, countertop water filters are typically less expensive than under sink alternatives. This low price point provides an accessible option for those looking to get clean, great-tasting water on a budget.


  1. Counter space: A countertop filter sits on your counter and takes up space. If you’re the type of person who wants a clutter-free countertop, you may want to look into under sink filters. Additionally, if you decide to put a water filter pitcher into your refrigerator for cold water, you will be taking up space within your fridge shelves or door.
  2. Size: With most pitcher-based countertop water filters, you are only allowed to filter as much water as the unit can hold. Many pitchers can only hold about one gallon of water at a time, which may not be enough for some people.

Aquasana Countertop Water Filters:

  1. Clean Water Machine: Claryum® technology filters 15 times more than the leading pitcher filter, with zero installation and a convenient pitcher that fits in your fridge door. While traditional pitcher filters use gravity to slowly trickle water over filter granules, Aquasana’s Clean Water Machine uses electricity to force water through ultra-dense carbon, resulting in 15x more contaminant reduction.
  2. All Aquasana under sink and countertop water filters leverage our Claryum®technology, which provides for maximum contaminant reduction, while maintaining healthy minerals for purely delicious filtered water. Claryum®technology uses activated carbon, catalytic carbon, ion-exchange, and sub-micron mechanical filtration to ensure you are drinking superior, great-tasting water.

    Additionally, all water filters require some maintenance when replacing the filters. We recommend you replace the filter in the under sink units and Claryum® Countertop filter about every six months, and replace the filter in the Clean Water Machine about every three months. All filters are eligible for the Water for Life® program, which ships replacement filters directly to you, right when you need them, at a discounted cost.  Whether you are looking for a water filter that reduces the most contaminants, or a filter you can take with you when you travel, Aquasana has an incredible lineup that will meet your needs. If you’re interested in learning more about what to consider when choosing a water filter, including whole house filters, our Sales Team is always to help.   SHOP COUNTERTOP WATER FILTERS