Under sink water filters

Under-sink water filters are by far the most popular type of water filters for residential use. Homeowners enjoy them because of their low-cost, easy maintenance and the fact that they don’t take up much space, staying hidden under the kitchen sink.

Another benefit of under-sink water filters is that they are available both in single-stage models (e.g. inline filter, one filter cartridge models) and multi-stage models (2 or 4-stage filters), allowing a perfect customization of the level of filtration you desire.

But are under-sink water filters a good fit for you? And should you install a single-stage or multi-stage model? We’ll help you shed on light on these questions and more in our comprehensive guide to under-sink water filters.

Best features of under-sink water filters

As best sellers of the water filter industry, the popularity of under-sink filters is cemented by the many advantages that you stand to gain if you choose to install an under-counter water filter. Here are some of the most notable features of under-sink water filters:

  • Easy installation: For the most part, water filters for domestic use are easy to install. This holds true for under-sink water filter as well, which are usually DIY-installable;
  • Cost-efficient: If you’re looking for efficient and budget-friendly filtration options, under-sink filters should be your go-to option. These filters are inexpensive both in terms of initial purchase price and upkeep costs;
  • Easy-to-maintain: If you don’t see yourself hands deep in water filter maintenance tasks, under-sink filters are for you. Apart from regular filter replacement, you don’t need to do anything else;
  • Compact models: If your home is too small to accommodate a large water filter system, you shouldn’t be alarmed – under-sink filters are compact, space-saving solutions that can be hidden under your kitchen sink;
  • Abundance of models: There is a great variety of filters that range from simple taste and odour removal filters to highly advanced fluoride, bacteria and heavy metal removal filters.

Inline filter or regular under sink water filters?

Water filters that are installed at a single point of use come in two variations – inline filters (i.e. filters that are installed in-line on your mains cold water line with push fittings) and regular filters, which require you to split your mains water line with a T-connector and install a separate filter tap.

Both filters have their advantages and disadvantages. Inline filters are a bit more difficult to install, but they allow you to keep on using your existing kitchen tap, filtering all the cold water that flows through it.

Regular under sink water filters, however, are easier to install, but they require you to add another tap to your kitchen sink for filtered water only. Thus, you will have a hot/cold water tap for unfiltered water and a single-dispensing tap for cold filtered water only.

With few exceptions, inline water filters usually come in single-cartridge models, thus, if you want a multi-stage filter, you should opt for a regular under-sink filter.

How to buy the best under sink water filters for your home?

If you feel it’s time to add a filter system to your kitchen, finding the ideal filter model can be a bit puzzling, especially that under-sink water filters come in several shapes and models.

Luckily, there some pointers you that can guide you in the right direction and help you narrow down your choices:

Filtration efficiency The efficiency of a water filter is determined by its contaminant removal capacity and filtered water output. Choose under sink water filters that can target most contaminants present in your tap water, without requiring you to compromise on flow rates.

Maintenance and installationIf you want to install your under sink filter on your own, choose a DIY filter. Even if you leave the installation part to a plumber, make sure you buy a filter that’s easy to maintain (e.g. under sink filters with quick-change filter technology).

BudgetDon’t focus only on the initial purchase price of a filter, but consider filter replacement costs as well. Choose under sink water filters with durable and high-availability filter cartridges.

Tap compatibility choose an under-sink filter that can be used with any single-dispensing or 3-way kitchen tap. If you want to keep your existing tap, choose an inline filter.

Any disadvantages you should know about under sink water filters?

Like any water filter, under-counter water filters have a few disadvantages too. Since they are installed at a single point of use, they filter the water at the water outlet they are installed at.

If you’re looking to have filtered water at every water outlet in your home, we recommend choosing a whole house filter.

Another drawback of under-sink filters is that they require you to install an additional tap. This can be avoided if you install an inline filter or if you replace your existing kitchen tap with a 3-way tap that delivers hot, cold and filtered water from a single tap.

Best under sink water filters for under £200

For this list, we’ve considered the contaminant removal, flow rates, purchase price and maintenance costs of these under-sink water filters to help you find an affordable kitchen water filter.

Osmio EZFITPRO-300 Undersink Water Filter Kit 15mm Push Fit

The EZFIT-PRO-300 combines the filtration efficiency of the Doulton Imperial Ultracarb Cartridge and an activated alumina filter for fluoride removal. The Doulton filter has an absolute filtration rating of 0.9 microns, which targets pathogens, chlorine, THMs, lead, insecticides and herbicides.

Activated alumina is a safe and non-toxic way to reduce fluoride levels in tap water. The AA filter has a fluoride absorption capacity of 500mg/l, thus, under optimal conditions, the AA filter can remove all fluoride compounds in your tap water.

The Osmio EZFITPRO-300 is one of those rare multi-stage inline under-sink filters that uses 15 mm push fittings for the inlet and outlet, which means that you can use it with your existing kitchen tap.

Filter cartridges in this Osmio filter system have a lifespan of 6 to 12 months.

BMB Nano Ultrafiltration (UF) Water Filter System

The BMB Nano UF water filter system contains 4 filter cartridges configured to target different types of contaminants. The filter uses easy plug & play filter components and quick-change filter cartridges for easy maintenance.

In terms of contaminant removal, the BMB targets the following types of water ingredients: chlorine, bacteria, VOCs, THMs, sediments, taste and odour altering contaminants, and a range of organic contaminants and industrial chemicals.

The system features two antibacterial sediment filters, one of which contains coconut shell carbon, a hollow fibre UF filter with 0.1 micron sized pores, and a coconut shell carbon filter for polished, pH stabilized filtered water.

The BMS requires a secondary tap for filtered water and it’s suitable for applications of up to 300 litres/day. All filters are replaceable at the same time (every 12 months).

Doulton HIP Ultracarb Water Filter System

Although this Doulton filter system features a single filter cartridge, it uses an exclusive ceramic-carbon block technology that filters down to sub-micron levels.

The HIP Ultracarb under-sink water filter reduces and removes 99.99% of particles down to 1/2micron, pathogenic bacteria, chlorine, VOCs, industrial solvents, asbestos fibres, dirt, algae, mould, improves taste and odour, and it’s 100% efficient against Giardia and Cryptosporidium.

The filter also contains ion exchange resin, which reduces lead and other heavy metals. The silver-infused ceramic structure of the filter confers it bacteriostatic properties.

The filter can be paired with reverse osmosis systems, and the cartridge has a filtration capacity of up to 2400 litres.

PurePro RS4000

The 4-stage PurePro filter not only removes contaminants from your tap water, but also re-mineralises water via the PurePro alkaline filter that makes up the 4th stage of this under-sink water filter.

The other three filters in this system (5-micron sediment filter and two granular activated carbon filters) remove suspended solids, 99% of chlorine and organic chemicals, reduce lead and heavy metals and targets pathogenic bacteria like Giardia and Cryptosporidium.

The filters have a service life of up to 6 months and their replacement is made easy by the twist and change quick-change cartridge replacement technology.

Healthy minerals lost during the filtration process are reintroduced by the alkaline filter, which adds trace amounts of natural minerals such as calcium, magnesium, sodium, and potassium ion that were removed by the filtration process.

Doulton Duo Filter Housing with Ultracarb & Cleansoft Candles

This Doulton under-sink filter has lime-scale reduction properties all the while targeting contaminants such as chlorine, particles, microorganisms, organic contaminants, and soluble lead.

The filters contain a blend of ceramic filter media and activated carbon, which last 3 to 6 months. Where water hardness levels are high, the CleanSoft candle should be replaced every 3 months.

This filter is suitable for those looking for an under-sink filter that can inhibit lime-scale formation and target contaminants.

Conclusion: Under sink water filters are affordable and efficient units

If you need a reliable under-sink water filter, the filters presented above can be a good fit, especially if you don’t want to invest in an expensive model. Some of these can be used with your existing kitchen taps, others require and additional filter tap. If you don’t want to have two taps on your kitchen sink, you can always upgrade to a 3-way kitchen tap for added convenience and functionality.