So you’re thinking about picking up a new water filter? Congratulations! Your daily life is about to get a subtle but worthwhile upgrade. While a home water filter might not be the sexiest or most dramatic addition to your daily routine, having access to purified water on-tap (perhaps literally, depending on the type of filter) brings a slew of health benefits and a touch of luxury to your everyday.

Here’s a rundown of the different types of water filters you can purchase right now. In this article, we’re looking at the main function of each device, their typical use cases, and average price points—but not so much the specific brands or products. So consider this the first port of call on your journey to better hydration.

Water Filter Pitcher

What does it do?

Pitcher-style systems are plastic or glass containers with a replaceable filtration cartridge or stick. Jug pitchers, which for most people are synonymous with the branded Brita Filter, are often shaped to be filled from the tap and stored in a refrigerator shelf. In fact, jug pitchers are often the go-to solution for those without an incorporated filter—Consumer Reports found that pitchers came second in a survey of the most-used water filters in the US after filters built into refrigerators.

Aside from jug pitchers, there’s a wide range of water-purifying containers, from water bottles with filter caps designed for the weekly commute, to aesthetically pleasing glass pitchers for the dinner table, to outdoor-ready bottles and filters for the campsite.

Why use this type of filter?

Whether on the go or in the home, a water filter pitcher is a convenient, manual solution to filtration. Despite being the most affordable type of filter in this list, a good quality, regularly replaced filter cartridge will reliably purify your water for a better taste and smell. So, if your concern is more culinary than health-hazard, a pitcher filter is a good option.

Price

Cheap. Most pitcher filters come in around the $20-50 mark, while filter bottles and the like can vary depending on the build quality, brand, and overall trendiness. In general, filter refill cartridges cost near on, or sometimes even more, than the price of the pitcher itself.

Ease of installation

Other than a quick swap-out of filter cartridges every few months, there’s no installation to worry about here, just fill and you’re good to go!

Level of filtration

According to the same Consumer Reports article, the purifying power of pitcher filters varies widely—the most of any type of filter on this list—so buyer beware!

As far as the well-known brands go, however, you can feel fairly confident that a pitcher filter will improve water flavor, remove odors, and protect you from a certain level of irritants and pollutants. Most pitchers and bottles use carbon/charcoal filtration, which according to Healthline, works through adsorption. This means that contaminants are naturally bound to the surface area of the carbon as water passes through the filter.

Most carbon filters do not filter for bacteria, viruses, or lead, but they should be good for chlorine and some metals.

Look on the packaging or the pitcher itself for the exact specs of a filter, and to make sure that it’s ‘NSF certified.’ Manufacturers will be more than happy to point out their product’s filtering power, so if it is a reputable brand,  you should be able to easily spot a list of specific filterable contaminants.

Other factors?

With pitchers being such a simple solution, it can be easy to forget to change filter cartridges. Most pitchers use a timer or pour-counter to estimate filter lifespan, while many bottles and charcoal filters have no way of marking purity level.

If your taste-buds are on point, you could rely on your senses to detect when you need a new filter (if your tap water is noticeably bad, this isn’t so difficult). Alternatively, most filters come with an estimated lifespan, so it’s simple enough to mark a calendar or set yourself another kind of reminder. If the filter has suddenly started running slow, that’s another signal that it’s time for a replacement.

Countertop Water Filter

What does it do?

Most countertop filters are basically static versions of a pitcher filter. Because they’re designed to stay in one place, countertop models attach directly to your kitchen faucet and often hold a much larger amount of water than a pitcher—or direct filtered tap water straight into your glass. A directional valve allows you to divert water from the tap, through a hose into the filter, where water collects in a butt or is directly poured, depending on the design.

Why use this type of filter?

If filtered water is a constant, everyday need, it makes sense to place a filtration device directly by the tap. That way, purified water is always there when you need it. While other types of water filters also provide this convenience, a countertop filter requires the least hassle in terms of installation, and can often be picked up for much lower price.

Price

Mid-range. Plastic and stainless steel filters can set you back anywhere from $50 to $100 dollars. Faster, more advanced, or premium design countertop filters can cost upwards of $175.

Ease of installation

Thanks to their simple design, countertop water filters don’t tend to require any serious kind of installation. This means they’re quick to get up and running, and can also be easily moved if necessary.

Most countertop devices are supplied with a valve that screws directly onto your faucet. To do this, you may need to unscrew and remove a piece at the very end of your tap, which is called the faucet aerator. An easy fix, even for those of us who are not so great at home repairs.

The filter then functions through a simple switch on the valve, allowing water from the tap to run through the filter hose rather than down into the sink. Many filter valves have an automatic shut off, meaning that they save you time by automatically returning to the vale to the sink setting when you close the faucet.

Level of filtration

Most countertop filters use similar replaceable carbon cartridges, which like pitcher filters, are great for removing chlorine, and other chemicals that affect water taste and odor.

However, probably in part to their more permanent use design, more countertop filters are equipped to remove heavier duty pollutants, such as lead and heavy metals, fluoride, nitrates, and even bacteria.

Other factors?

Because they attach directly to the faucet, there may be a level of frustration with a countertop model, depending on the amount of counter space you have, the setup of your kitchen, and the size of your sink. Another common complaint about this type of system is that it can affect the water pressure coming out of the faucet.

While almost all countertop filters include a value to control whether the water flows into the sink or into the filter, continually switching between the two may test the nerves of some (if that sounds like you, be sure to find a filter with an automatic shut off valve.)

Refrigerator Water Filter

What does it do?

No points for guessing this one! A refrigerator water filter dispenses water through an internal water system of a fridge, providing instant filtered water that’s also pleasingly chilled. Fridges that include a built-in water filter may offer the device as an add-on to the price, and often also include an icemaker, making use of the freezer component of the system.

Why use this type of filter?

If you’re currently keeping a steady supply of bottled water inside your fridge, there’s really no reason not to make the switch to an integrated filter (if your fridge can incorporate one.) You’d be getting the same purified, chilled water, without the nasty environmental negatives of single-use plastics, as well as avoiding the growing concern about microplastics. As this article from Live Science describes, a study of 250 bottles from 11 brands revealed microplastics in 93 percent of samples. Drinking bottled water means ingesting microscopic amounts of plastic that enter the water either from the bottle itself, or from when you twist off the cap.

Price

Mid-range to pricey. Expect a premium on the base cost of the fridge itself. Consumer Reports lists the average price of filter replacements as $60, making them more expensive than pitcher cartridges—although they may last a little longer.

Ease of installation

Probably a little difficult, if you had to manage installation yourself. With fridge filters coming already integrated with your fridge, however, all you need to do here is swap out the carbon cartridge according to product recommendations, making fridge filters equivalent in these terms to pitchers and countertop models.

Filtration level

Again, we’re looking at carbon filters, for the most part. Meaning that fridge filters are also intended to heighten the flavor and purity of tap water that’s already generally safe for consumption, rather than turning undrinkable water into a hydrating beverage.

Other factors?

There is some debate as to the hygiene and longevity of refrigerator filters over time. Because the filtration system is usually contained within the inner workings of the fridge, it can be difficult to visually assess the filter hoses and reservoir for signs of contamination. According to Waterlogic, despite keeping your food fresher for longer, refrigerators are rarely as clean as you might at first think. Thanks to the constant presence of moisture and organic matter, fridges can become home to waterborne bacteria, which can make its way into the filter system and pass through a carbon component. The risk is increased substantially if you leave food to mold, or even food that harbors E Coli. (To be clear, some carbon filters are certified to remove these contaminants, but not all—and their ability to do so will degrade with use). Likewise, having the filter cartridges seamlessly built into your fridge may make it easier to forget to change them.

A common complaint of fridge systems is that, while the filter may purify water coming from the tap, the taste is then re-tainted by strong smelling foods from the fridge or freezer—though this issue seems to be more common with ice makers than water filters.

Faucet-Mounted Water Filter

What does it do?

A streamlined version of the countertop filter, faucet-mounted water filters sit directly on your faucet and filter water in-stream, as it pours from the tap into your glass.

Why use this type of filter?

Either you don’t feel the need to have a larger container of filtered water ready to pour, or you find the task repeatedly filling up a jug-style filter arduous. Or, perhaps you’re highly limited in terms of fridge, counter, and cupboard room, so need a space-saving option. A faucet-mounted filter offers the most economical use of space on this list, for the price of a slightly slowed flow from your tap.

Price

Cheap. Look to pay a similar amount for an on-tap filter as you would for a pitcher-style product (So between $30 and $80.) Like all types of filter, there is some differentiation between price, build quality, pleasing, aesthetic, and the filtering power of the device.

Ease of installation

Installing a faucet-mounted filter is no different to installing a countertop model. They generally require you to remove the aerator—the very end of the faucet—and then screw the filter directly onto the tap.

Level of filtration

More replaceable carbon cartridges (see above types). Because on-tap models are much smaller than pitchers, countertop, and fridge filters, they may take longer to filter the same amount of water. For the same reason, they’re also not able to store up a reservoir of ready-filtered water.

Other factors?

Faucet-mounted filters require you to manually switch between filtered and unfiltered water, so this could pose an annoyance if you regularly need to speed up your faucet’s water flow for filling larger containers. On this point, most mounted filters will noticeably reduce the water flow from your tap.

More importantly, not every faucet will accept a mounted filter, and not every filter will fit every faucet—so make sure you know the specs of what you’re buying. If your tap has a pullout hose or spray head option, it’s unlikely to be compatible. Likewise, if your tap is on the flimsier side, it might not be a great idea to add the extra weight of a filter.

Undersink Water Filter

What does it do?

Undersink filters are professionally integrated underneath a kitchen sink, using mains pressure to push tap water through a large, dense filter before it reaches your tap.

Why use this type of filter?

These filters offer the most streamlined, efficient, and aesthetically pleasing filtering solution. They’re also amongst the most powerful in terms of filtration level. So, while expensive, an under-sink model will give you great-tasting, safe water, and look good while doing so. Most under-sink models either send water directly through your pre-existing faucet or through a secondary tap, mounted around your sink, allowing you to easily filter a whole lot of water throughout the day.

Price

Expensive. Due to their permanent fixture, installation requirements, and superior filtering power, under-sink filters can set you back $100 to $300 dollars, notwithstanding any costs installation or filter replacements. Take into account labor, and any alterations that may need to be made to your countertop, and costs begin shooting towards the $1000 mark.

Ease of installation

Many under-sink systems require making some modifications to your kitchen plumbing. While these modifications are not significant, they can often require the services of a professional plumber. There are some under-sink filters that can be installed by the consumer, but even these present a lengthier and more complex option than pitchers, countertop, or faucet-mounted systems.

Level of filtration

Unlike most types of water filters on this list, under-sink filters take advantage of the water pressure coming from your mains system. They use this pressure to push water through the filter, instead of simply relying on the force of gravity to collect purified water. This means that under sink filters can be denser, and are therefore capable of removing smaller or more soluble contaminants and pollutants.

While they still mostly use charcoal systems, this ranks under-sink models among the most effective water filters, with the least disruption to your kitchen and the least reduction to water flow. Many models are capable of removing higher-order materials such as lead, mercury, and pharmaceuticals.

Other factors?

Under-sink water filters are a reasonably expensive investment and are really intended as a permanent fixture. This means they’re probably of less interest to most renters and those in short-term accommodations. They also take up a significant amount of room underneath your sink. So, if you’re running short on cupboard space, consider whether you can sacrifice room in the name of purified water.

Reverse Osmosis Water Filter

What does it do?

The ‘black sheep’ of the water filter landscape, reverse osmosis filters take a different approach to water purification, using a semi-permeable membrane to allow water through while catching contaminants and bacteria.

Why use this type of filter?

A serious benefit of reverse osmosis membranes is their usable lifespan. While the other filter types on this list need to be replaced after a few months to a year, reverse osmosis filter membranes only need to be changed every two years, on average. Many RO systems also boast more advanced filtering power than carbon-based filters.

Price

Expensive. You can pick up an under-sink RO filter for a similar price to other types of under-sink systems (so think $150 to $300). Again, installation/labor costs can double or triple this number, especially if you’re making alterations to your countertop.

Ease of installation

Most under-sink systems require making some modifications to your kitchen plumbing—so don’t be a have-a-go hero. Employ the services of a professional to ensure that your kitchen doesn’t turn into one big reverse osmosis reservoir.

Level of filtration

In basic terms, osmosis is a key biological process, occurring all the time inside your body and out in the world. Osmotic pressure is created when two or more different concentrations of a solution exist across a permeable membrane. This pressure causes water and other liquids to move across a membrane, always in the direction of a more concentrated solution, seeking an equilibrium.

A reverse osmosis filter does exactly what it sounds like—it reverses this process, in order to produce a purer level of water from the denser solution of contaminants existing in your tap water. As tap water passes through the filter, external pressure is applied, overriding and reversing osmotic pressure. This encourages tap water to pass through a membrane (or series of membranes), which you can think of as basically a very fine strainer, catching particles as small as 0.001 micrometers, depending on the product.

Some OR filters will also combine this process with an additional carbon or UV filter, for the ultimate in-home water filtration.

Other factors?

Filtering through osmosis is slow in comparison to carbon filtration, meaning that RO systems require a built-in reservoir to collect water, which can therefore run dry with heavy use. The micro-level of filtration also means extracting materials that don’t necessarily need to be removed from your water supply—calcium, magnesium, and fluoride, for example—all of which you may be looking to keep in your tap water for their health benefits.

Nonetheless, OR filters remain a highly powerful, industrial level filter. Some filtration plants even use reverse osmosis to turn seawater into a drinkable liquid, as this Scientific American article describes.

Conclusions

Do you need a filter to deal with annoyingly unpleasant tastes and odors in your tap water—or—are you concerned about the presence of more harmful pollutants in your mains water supply? The answer to this question takes care of much of the decision-making process when it comes to water filter types.

While there are heavy-duty filtration options available in all design types listed here, most home water filters utilize carbon filtration cartridges. So, if you do need a bacteria or heavy-metal eradicating filter, you’ll be picking from a much smaller pool of specialist filters and reverse osmosis systems.

For the rest, the choice comes down to price and convenience. Don’t mind manually filling a filter reservoir? Then go for a pitcher or countertop model—both of which offer value and luxury designs. Looking for something integrated? Then consider under-sink, faucet-mounted, or fridge filters, depending on the specifics of your kitchen.

A note on filter certifications

Whatever kind of filter you select, always look for genuine NSF or equivalent filtration certifications, to ensure that a filter can really do its job. As a minimum, you’re looking for a filter to be compliant with three NSF International numbered regulations: 42, 53, and 401.

  • 42. This certifies that a filter is able to remove chlorine and other taste-affecting chemicals. It also says that the materials used to construct the filter are non-toxic, guaranteeing the safety of the filter itself. It would be depressingly ironic to find that your filter is dangerously contaminating tap water that might taste bad, but is otherwise safe to drink. So make sure that the filter you choose is a product with this rating.
  • 53. This certifies that a filter is capable of taking on a more advanced level of pollutants and contaminants, such as parasites, asbestos, and heavy metals like lead. Check individual products for a full list of filterable materials.
  • 401. This certifies that a filter is able to remove trace elements, such as chemicals from pharmaceuticals like ibuprofen and Deet. Most water filters do not come with this level of certification.

Here’s the NSF’s official database, which you can use to find out exactly what your filter model is certified to protect you against.