9 Best Water Filters of 2024, Tested & Reviewed by Experts - Good Housekeeping

✔️ Type and capacity: For pitchers, water bottles and other dispensers that hold water after it's filtered, you'll want to keep in mind size and weight. Larger containers are ideal for refilling less often, but they will often be heavier and may take up more space in the fridge or your backpack. A countertop model saves space in the refrigerator and often holds more water, but it requires room on the counter and will be room temperature water.

With under-the-sink water filters, faucet filters, shower filters and whole-house filters, there's no need to worry about size or capacity as these instantaneously filter water as it flows through.

✔️ Filtration method: One thing to note is that many filters incorporate multiple filter types to achieve various contaminant removal. With some, the contaminants they remove can vary widely, so it's best to check what the model actually filters, so it suits your needs. The surest way to determine this is by checking which NSF standard the filters are certified for. For example, some standards cover only lead, like NSF 372, while others also include agricultural and industrial toxins, like NSF 401. Otherwise, here are the different water filtering methods:

• Activated carbon is the most common water filter. The carbon-based filter acts like a magnet, absorbing contaminants from the water. Multi-stage filters, or 2-stage filters, might also include a pre-filter to remove larger sediment, as well as a second carbon filter to improve odor and taste. If necessary, sometimes there is even a third filter, maybe with an additional carbon block or a UV sterilizer to kill bacteria and viruses.
• Reverse osmosis (RO) is a newer type of filter that captures contaminants by pushing pressurized water through a semi-permeable membrane. While extremely effective, it's more expensive and less efficient — many systems require a tank that won't fit under your sink. Reverse osmosis filters are only seen with water systems because it needs pressure to work. Our experts first recommend testing your water to determine whether a conventional filter can cover your filtering needs. Most water filters use either a carbon filter or a reverse osmosis water filter, which can also include a carbon filter.
• Ultrafiltration (UF) is another technology you might also hear about. Like RO, it forces water through semipermeable membranes. Because the pore size of the UF membranes is bigger, these systems don't capture all contaminants, including total dissolved solids (TDS) like chlorine and fluoride; we did not review any UF systems for this reason.
• Mineral/alkaline filter adds minerals like potassium, magnesium and calcium. According to the Mayo Clinic, alkaline water has a higher pH level than plain tap water. Some studies also suggest that alkaline water might help slow bone loss. However, further studies are needed to determine whether these benefits are long-term.

✔️ Filter replacement frequency: Check how often you have to replace the filter. If you dread changing the filter or simply forget, you may want to look for a long-lasting filter. Also, if you buy filters for the shower, water pitcher and sink, you'll have to remember to change each of those separately, so it might be smart to consider a whole-house filter that requires only one filter replacement for the entire home.

No matter which water filter you opt for, it's no good if you don't change the filter as recommended. "The performance of the water filter depends on the quality of the water source and whether or not the filters are replaced regularly," Aral said. Some models come with indicators, but if a model doesn't include one, a slower flow rate or different-colored water are signs that you need to change the filter.

✔️ Price: Consider both the upfront price of the water filter device and the filter refill costs. A water filter could cost more initially, but the price and frequency of the filter refills may save money over the long term. But that's not always the case, so be sure to calculate the yearly cost of replacements based on the recommended schedule for changing.