Are Under Sink Water Filters Worth It?

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Considering buying an under-sink water filter? Wondering whether it’s worth your hard-earned cash?

Under-sink water filters cost anything from $150 to $600, so we don’t blame you for being cautious about investing in one for yourself. In this guide, we’ll be sharing everything you need to know when deciding whether an under-sink water filter is worth it.

📖 TL; DR

Under-sink filters are worth it if you want to eliminate your bottled water use and you want to filter your drinking water on demand. These filters aren’t worth it if you want to filter the water in your whole home, or you don’t have around $150 per year to spend on maintenance.

🤔 What Are Under-Sink Filters?

We know that if you’ve clicked on this article, you probably already know what under-sink water filters are.

But perhaps you don’t know for sure – and you can’t figure out whether an under-sink filtration unit is right for you until you know exactly what it is and how it works.

An under-sink filtration system is a unit that filters your water by sending it through several different filter media. As the name suggests, this type of unit is installed underneath your kitchen sink.

There are usually two or three different filter stages in an under-sink filtration unit. These include a sediment filter, one or several carbon filter cartridges (namely activated carbon or carbon block filters, sometimes combined with KDF or ion exchange), and a polishing filter. An under-sink reverse osmosis system also features a semi-permeable membrane.

An under-sink filter is hooked up to your cold water line, so it delivers filtered water from your faucet (or from a dedicated faucet, depending on the type of system you buy). This means you get access to filtered water on demand.

clearlyfiltered under sink direct connect system

Under-Sink Reverse Osmosis Water Filters

Reverse osmosis filters have a more complex design than standard under-sink units. RO systems are centered around a semi-permeable membrane, and force water through this membrane at a high pressure. The membrane’s pores are so tiny that only water particles can pass through.

RO under-sink filters usually have additional components, like a water storage tank, a separate faucet, and a drain line. While RO filters offer a more thorough filtration process than the average under-sink unit, they’re also more expensive and wasteful.

Installing an under-sink filter

Learn how to choose an under sink water filter in our expert’s guide.

📑 Pros and Cons of Under-Sink Filter Systems

👍 Pros

The pros of under-sink water filters are:


The convenience of an under-sink treatment system is undeniable. You switch on your faucet and you have instant access to filtered water. You don’t have to fill a pitcher jug, add chemicals, or do any of the hard work yourself. Your under-sink filter system will do it all for you.


Not a fan of filtration systems that take up valuable counter space in your kitchen? You’ll be pleased to know that under-sink water filters can be hidden away in the cabinet beneath your sink. You’ll only need to look at the unit when you make a filter replacement, so it certainly won’t tarnish your otherwise impeccable kitchen.

clearly filtered under sink system

Removes Dangerous Impurities

The obvious benefit of under-sink water filters – and probably the reason you’re looking to buy one – is that these filters remove a whole host of dangerous contaminants from your water, including heavy metals, chlorine taste and odor, VOCs, nitrates, and more.

An RO system with a reverse osmosis membrane goes one step further than this, removing virtually all total dissolved solids and producing purified water. Not only should your water taste better after installing an under-sink unit, but you’ll feel safer drinking it, too.

Long-Lasting Filters

The average under-sink filter unit has three filters and requires a filter replacement every 6-12 months. Compare this to other filter systems on the market (for instance, pitcher filters, with a 3-month filter lifespan), and the maintenance is minimal.

Filtered Water On Demand

Even an under-sink filter with three or more filtration stages delivers a fast flow of water to your faucet. That’s because these types of filters are powered by your water pressure, not gravity, so flow rate is much faster. As soon as you turn on your faucet, water will arrive.

Reverse osmosis filter systems take a bit longer to produce filtered water, but you won’t know, because most store treated water in a tank that can be delivered straight away.

Getting water from under sink system

More Affordable than POE Systems

If you don’t want to filter the water in your shower or washing machine, there’s no point in spending thousands of dollars on a whole house filtration system. Under-sink water filters are an affordable means of filtering your drinking water.

Help you Save Money

If you usually buy bottled water to avoid the consumption of harmful contaminants in your tap water, you can cut the habit once you install a filter underneath your kitchen sink. Under-sink water filters pay for themselves in a matter of months – and they don’t contribute to single-use plastic waste, either.

👎 Cons

Challenging to Install

Most under-sink water filters are designed for “easy installation”, but the installation process is still more difficult for this type of filter than it is for a simple countertop filter. After all, you’ll need to intercept your cold water line, and, in the case of RO filters, you’ll need to install a drain line and water storage tank. Some filters also require a separate faucet, installed next to your current faucet on your sink.

While most people should be able to install under-sink filters, a lot of work is involved in the process, and the manufacturer’s instructions aren’t always clear.

Tightening the connection

Out of Some Budgets

Just because under-sink filters are cheaper than whole house filters, that doesn’t mean they’re affordable for everyone. The thought of spending more than $200 on a single filtration system is difficult for some people to justify. Replacement filters are much more expensive than the filters in a water pitcher filter, too.

Slightly Reduces Water Pressure

We said that under-sink water filtration units deliver a good water flow, and they do. But when you’re sending water through several filtration stages, of course the flow will be slower than if there’s no filter intercepting your water line. You may have to wait a couple of seconds longer than usual to fill a glass of water.

Removes Beneficial Minerals (RO only)

RO filter systems don’t only filter water – they produce pure water with virtually no contaminants. While this is beneficial in many ways, it also means that healthy minerals, like magnesium and calcium, are removed from water.

We get plenty of these minerals from our diets so it’s not the end of the world – but they do contribute to a pleasant alkaline taste in water, and without them, water can taste quite “flat”. However, reverse osmosis is not distilled so it is important to know the difference.

Flat-tasting water

💰 Why Are Under-Sink Water Filters Worth The Investment?

Different types of under-sink filter systems have different features and benefits, but generally, here’s why these filters might be worth it for you.

You Have the Budget for an Under-Sink System

Under-sink water filters are mid-range or expensive products, depending on the type of filter you buy, and from which brand. You’ll need a few hundred dollars upfront, and $100 or so every year to buy replacement filters. If you have the funds for an under-sink system, and you’re happy to spend them, this type of drinking water system is worth it for you.

You Want Filtered Water on Demand

Under-the-sink water filter systems deliver filtered drinking water on demand. If you’d rather enjoy a filtered cold water supply as soon as you turn on your tap, this type of filtration unit just makes sense.

You’re Committed to Maintenance

Under-the-sink water filtration systems need regular maintenance. The sediment and carbon filters last for 6-9 months on average, and the post-filter has a filter life of 12 months. In reverse osmosis systems, the semi-permeable membrane lasts on average for about 2 years.

Replacing water filter cartridge

You Prefer a More Permanent Solution

Of course, no water filter is truly permanent – you could uninstall any type of filter if you weren’t happy with it. However, because under-sink filters are hooked up to your cold water line, they have a more “permanent” feel than other filter types, like countertop filters and water filter pitchers. If you’re happy with this setup, then a water filter system under your sink is worth it for you.

You Buy a High-Quality Filter

A filtration system for under your sink is only worth it if it’s a high-quality product. Look for filters that are highly reviewed by hundreds of customers, and are offered by the most reputable, reliable brands in the industry. A filter that lives up to expectations is a far worthier investment than one that falls short of the mark.

The Pros Outweigh the Cons

Take a look at the Pros and Cons section of this article again. Do the pros outweigh the cons from your perspective? If they do, it’s the best indication you’ll get that this type of water filter is worth it for you.

💸 Why Aren’t Under-Sink Water Filters Worth The Investment?

Now we know why an under-sink water filter system might be worth it for you, let’s look at why under-sink filters might not be worth it.

You Can’t Afford the Purchase or Maintenance

The upfront cost of an under-sink water filtration system is hundreds of dollars. You’ll also need to pay the long-term costs of replacing the filters every year, which typically exceed $100. If you can’t afford – or justify – the costs of owning an under-sink water filter, it’s not worth it for you.

That doesn’t mean you should rule out water filters entirely. Consider affordable filters, like water pitcher filters, which cost less than $50 upfront and have a minimal ongoing maintenance spend.

Or learn more about the difference between under sink vs refrigerator water filters.

You Want to Filter the Water in Your Whole Home

Under-sink water filters can only filter the water that leaves your kitchen sink faucet. If you want a filtration system that treats the water in your entire home, under-sink filters won’t be worth it for you.

Instead, consider a point of entry filtration system, called a whole house water filter system. This system will treat your water before it even flows through your hot water heater, providing filtered hot and cold water throughout your plumbing, pipes, and appliances.

Springwell CF whole house filtration system

You Live in Rented Accommodation

Most landlords don’t allow any types of “permanent” installations or anything that may remain as a change to the property if you, the tenants, decide to move on. For this reason, under-sink systems are usually out of the question if you rent your property. An under-sink filtration unit probably isn’t worth it for you, but you can consider other, non-permanent solutions, like countertop filters and faucet-mounted filters.

The Filter Quality is Poor

Not all water filters are equal, and some under-sink water filters aren’t worth it for anyone. We’ve tested dozens of under-sink filtration systems over the years, and we know that some are an exceptional value for money, while others are a completely wasted investment. If you want to spend wisely on a system that’s worth your money, check out our best under-sink water filter reviews and buyer’s guide.

The Cons Outweigh the Pros

Once again, look at the Pros and Cons section of this guide. If you can’t ignore the cons, no matter how tempting the pros, it’s a suggestion that even the best under-sink water filter isn’t worth it for you – yet. You might change your mind in a few months or years.

📝 Summary: Are Under Sink Filters Worth It?

Under-sink water filters are a convenient, clutter-free water filtration solution. These filters deliver clean water whenever you need it, and are a reliable means of removing everything from chemicals to heavy metals. However, under-sink filters can be challenging to install, especially for people with little DIY experience, and their cost is too high for some budgets.

If you’re looking for a targeted tap water filter that you’re happy to install and maintain for the perk of filtered water on demand, an under-sink unit is worth it for you.

If you prefer a more affordable filtration solution, we recommend considering water filter pitchers, instead. There are plenty of pitchers that can remove just as many contaminants as under-sink water filters, if not more.

Or, if you’re looking for a solution for your whole home, and you have a bigger budget, consider a whole house filter. This type of system filters the water supplied in your entire home’s plumbing, appliances, and faucets.

  • Jennifer Byrd
    Water Treatment Specialist

    For 20+ years, Jennifer has championed clean water. From navigating operations to leading sales, she's tackled diverse industry challenges. Now, at Redbird Water, she crafts personalized solutions for homes, businesses, and factories. A past Chamber President and industry advocate, Jennifer leverages her expertise in cutting-edge filtration and custom design to transform water concerns into crystal-clear solutions.

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