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How Does a Water Filter Work?

A water filter purifies water from the mains supply by capturing sediment and particles and absorbing or precluding potentially harmful substances from the water passing through it.

Why Do You Need a Water Filter?

Potable water from the mains supply in Britain is amongst the safest in the world, yet there are many factors which can lead to variations in odour and taste as well occasional outbreaks of water-borne parasites such as cryptosporidium. In addition to this, in certain hard water areas, scale formation can block pipes, damage kettles and coffee machines cause heating appliances to run inefficiently.

To avoid these issues, many people purchase bottled water, though the environmental damage caused by the production of bottled water and discarded plastic bottles has been well publicised.

Water filters, therefore, provide a way of improving the taste and odour of mains water as well as limiting our risk of exposure to potentially harmful contaminants that may be present in the water supply, that is far more environmentally friendly than drinking bottled water.

What Types of Water Filter Are There?

There are a range of different water filters which vary according to the desired functionality as well as the type of impurities that need to be filtered out. If you have an existing water filter system, please check the brand and model first to ascertain which type of replacement water filter is required. If you are unsure, please contact the team at Andrew’s Water Treatment so we can find the right filter for you. Some of the most popular types of water filter are:

Inline Water Filters

Inline water filters are a convenient means of providing a constant supply of filtered water to your premises as they fit directly to your water line or appliance. As they don’t require a separate filter head, they’re also ideal for locations where space is limited, such as under a sink. Inline water filters use a range of filtration media making them highly effective not only for reducing chlorine taste and odour but also for reducing chemical, bacteria and heavy metal content. Some elementary plumbing knowledge is required to install a simple domestic drinking water system but, once fitted, a replaceable water filter cartridge will usually last between 6 to 12 months. Inline water filters are most often used in under-sink water filter systems found in domestic premises although some models can be used for vending machines, water fountains, ice machines, domestic fridges, showers (ideal for people with sensitive skin) and coffee machines.

Top Brands of Inline Water Filter

  • Everpure Water Filters – Pentair Everpure produce a huge selection of filters for both domestic and commercial foodservice applications such as coffee, ice and vending machines
  • Water Gem Water Filters – Water Gem is Europe’s best-selling under-sink filtration system due to its affordability and easy installation.
  • Hydro + Water Filters – Suited to a variety of purposes including domestic and vending applications, these filters are manufactured in the UK and come with a range of connection options.
  • 3M Water Filters – Previously known as Cuno, Andrew’s Water stock the popular CS, AP2 & AP3 ranges as well as the SGP ScaleGuard Pro and HF High Flow series. Suitable for domestic and commercial uses.
  • Omnipure Water Filters – A well-established US-based water filter manufacturer that focus on reducing contaminants that lead to taste, odour and discoloration in potable water. Andrew’s Water Treatment are proud to be one of the few UK distributors of this brand of filter.
  • Franke Water Filters – Andrew’s Water stock a range of Franke compatible Doulton water filters. These high-standard ceramic filters are designed to remove bacteria, cryptosporidium, giardia and sediment as well as chlorine which can affect the taste and smell of water.
  • Taste Great Water Filters – Designed to fit Taste Great Water Systems, this new brand focuses on easy DIY installation without the need for plumbing skills. As its name suggests, it improves the taste and odour of mains water as well as stopping sediment and other undesirable impurities from rusty pipes.
  • Brita Water Filters – We stock a range of Brita Purity Quell water filters as well as a selection of Brita compatible coffee filters.


Water Filter Cartridges

Water filter cartridges or ‘drop-in’ filters are designed to fit inside industry-standard water filter housings. They are made in a variety of sizes, with the most common being 10” and 20” and are offered with various different media types depending on the type of contamination being reduced.

The filtration level of a water filter cartridge is measured in microns, a unit of measurement equal to 1 millionth of a meter in length. To get an idea of scale, the average cross-section of a human hair is 50 microns. The smaller the micron rating, the smaller the size of particle the cartridge can remove.

Water filter cartridges have the advantage of being very low-cost and easy to replace compared to other types of filter. They require changing when the pores of the filter media become clogged or the media becomes saturated with contaminants – generally this will occur after 6 or 12 months use, depending on the filter. When this happens, simply remove the cartridge from the housing, clean the unit and replace with a new cartridge.

Sediment Filters

Sediment filters are produced either as ‘drop-in’ cartridges as described above or else as bag filters. Sediment filter cartridges are generally made of a durable material such as polypropylene which is either pleated, spun or wound extremely tightly in order to preclude unwanted particles.

Bag filters, as the name suggests, basically consist of a polypropylene bag which catches contaminants as the water passes through. Carbon block media is also effective at reducing sediment due to its fine pore structure, though GAC (because it is made up of separate carbon granules) is not a suitable filter media for sediment filtration.

Ceramic Water Filters

Ceramic water filters originated in 19th century Britain when Henry Doulton first discovered that filtering potentially harmful water through a porous ceramic material removed many impurities present in the water supply (specifically from dirty Thames river water). This was revolutionary at the time as many people suffered from water-borne illnesses such as cholera.

Although modern today technology has greatly advanced, the principles of a ceramic water filter remain the same – utilising the small and complex pore structure of ceramic filters to remove 99.9% of pathogenic bacteria and disease causing cysts, with the added benefit of removing unpleasant tasting contaminants such as chlorine.

Ceramic water filters have many benefits, for instance, the ceramic filter elements can be cleaned in order to extend the life of the product and cut down on the need for a replacement filter. They also allow beneficial minerals to pass through the filtration system, providing a safe and healthy filtered tap water.

Fridge Filters

You need to be extremely careful with filtered fridge water, with built-in fridge water supplies carrying a far higher risk of picking up microorganisms such as coliform and salmonella than a plumbed-in mains water supply. 

That’s why, if your fridge has the ability to dispense drinking water, you will need to ensure the fridge water filter is changed at regular intervals, regardless of the make and model.

We stock a range of fridge water filters including internal fridge filters and externally mounted fridge filters which are compatible with a variety of fridge brands including Samsung, Bosch, Neff and Siemens.

Coffee Machine Water Filters

As coffee connoisseurs will tell you, filtered water is extremely important for creating great tasting coffee. However, coffee machines can be susceptible to limescale issues in hard water areas. Using a water filter can reduce the hard mineral content, reducing limescale build up and extending the life of your equipment. In fact, a water filter can be the difference between having an espresso machine for just a few years compared to over 10!

Many of our coffee machine water filters can be used to provide the required water hardness as well as remove chlorine, lead and other impurities which can affect the taste and smell of coffee. We also supply filters for commercial foodservice and speciality coffee applications.

Water Filters for Commercial Foodservice

Andrew’s Water are experts in the supply of water filters for commercial foodservice equipment such as combi ovens, steamers, ice machines, espresso machines and warewashers. With the cost of repairing or replacing commercial foodservice equipment being so high, a water filter is cost effective way to lessen the likelihood of inefficiency or damage due to scale build-up.

Unsure of Which Water Filter You Require?

Choosing a water filter can be difficult, particularly if you are unsure about the quality or hardness of your local water supply. If you are unsure of anything or need us to identify which water filter is best for your requirements, please contact us.

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