Why do we filter water?

water filter

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Water filters act like a sponge removing unwanted impurities from water such as hardness, odour, bacteria & sediment. In doing so the water quality is improved and by using specific filtration methods you can make water pretty much fit for any purpose whether it’s for human consumption or use in making foods, manufacturing and more. One of the most commonly known uses of water filters is on coffee machines to improve the taste & drinking fountains in gyms but this is just the tip of the iceberg.

The most basic necessity is to remove unwanted contaminants from water so as humans we can consume & use the safest & cleanest water possible.

The different types of water filters 

  1. Mechanical Filters
  2. Absorption Filters
  3. Sequestration Filters
  4. Ion Exchange Filters
  5. Reverse Osmosis Filters

These types of filtration can be utilised as one or an assortment to produce the required end result and quality of water required.

Covering 71% of the earth’s surface we are also made of about 75%. Waters importance spans a huge number of applications such as agriculture, science, medical, transportation, heating, recreation, food processing, washing and of course drinking.

Drinking water comes from a treated municipal supply which is safe but often has unpleasant tastes from odours and chemicals such as chlorine which is used to disinfect water and keep it free from bacteria.

Depending on where you live in the country, water hardness can vary hugely. Hard water is responsible for lime scale deposits for instance in kettles & boilers and this can create costly repairs, placements without being properly managed. Water filters can help with all of these issues.

Mechanical Filters

The best way to describe mechanical filtration is the process of physically removing sediment, dirt and tiny particles from the water by passing it through a mesh filter. The use of normal meshes deals with large debris whereas ceramic filters have an extremely complex pore structure for filtration of pathogenic organisms. In simple terms if you passed water through a pipe which was packed with sponges the water would come out the other side much cleaner as the sponges would not allow the dirt to pass through.

Micron ratings are usually given to mechanical filters which help define the size of the debris the filter can remove.

Absorption Filters

Carbon is commonly used in absorption filtration as it is super effective at capturing water-borne contaminants.

Carbon has a high internal surface with lots nooks and crannies in which it traps chemical impurities like chlorine and more.

Most domestic filters for drinking water and for example on gym water fountains use a granular active carbon (GAC) which remove unwanted tastes and odours by absorption.

Sequestration Filters

Sequestration is the action of chemically isolating a substance. Food grade polyphosphate is commonly used in scale inhibiting filters to sequester the calcium and magnesium minerals which cause limescale and corrosion.

However, polyphosphate is generally only introduced in very small amounts and it only inhibits scale rather than eradicating it. This means that polyphosphate does not soften the water but instead works to keep the minerals within the solution, preventing them forming as scale on any surfaces they come into contact with.

Due to the hard minerals still being present in the water, scale inhibition isn’t suitable for all applications. Instead, water softening using a process such as ion exchange is usually recommended in water areas with alkalinity levels of 180ppm or more (very hard water) and applications where water is kept at a constant temperature of 95°C or more.

Ion Exchange Filters

Ion exchange is a process used to soften hard water by exchanging the magnesium and calcium ions found in hard water with other ions such as sodium or hydrogen ions. Unlike scale inhibition, ion exchange physically removes the hard minerals, reducing limescale and making water suitable for applications where it is kept at a constant high temperature e.g. in commercial coffee machines.

Ion exchange is most commonly carried out using an ion exchange resin which normally comes in the form of small beads. A similar type of resin is used in some Water Softeners and in the case of a water softener the resin utilises sodium ions which need to be periodically recharged to prevent the resin becoming ineffective. As water filters are usually sealed units you would simply replace the filter with a new one though it should be noted that

Calcium Treatment Units (CTUs) can be returned to the supplier and regenerated.

Resins that utilise sodium ions aren’t usually used in drinking water filters as the amount of salt (sodium) that can be present in drinking water is legally limited to 200 milligrams/litre. As sodium ion exchange increases salt levels, a hydrogen based ion exchange resin is the preferred option for filters.

Reverse Osmosis Filters

Reverse osmosis (RO) is the process of removing dissolved inorganic solids (such as magnesium and calcium ions) from water by forcing it through a semipermeable membrane under pressure so that the water passes through but most of the contaminants are left behind.

Reverse osmosis is a highly effective way of purifying water and is usually combined with a number of other filters such as a mechanical (sediment) filter and an absorption (activated carbon) filter in order to return water with few contaminants remaining.

Reverse osmosis systems use water pressure to force water through the membrane so it uses no electricity, though a certain amount of waste water is produced that has to be sent to the drain. The extra filters involved in multi-stage water filtration can make a reverse osmosis unit more expensive than other filtration methods but in applications where 99.9% pure water is required, RO offers the finest level of filtration available as is increasingly being used to treat water made for Coffee


Each filtration method has limitations on what it can remove, so most water filters or filtration systems use a combination of methods to achieve a specific level of water purity. To give an example, household water jug filters will generally use mechanical, absorption and ion-exchange whereas inline filters will utilise mechanical and absorption with the possible inclusion of sequestration if the filter is designed to inhibit scale. Reverse osmosis systems can utilise mechanical, absorption and of course reverse osmosis depending on how many stages the RO system has.

By understanding of the five different methods by which water can be filtered and the way they can be combined, you should hopefully find it easier establishing which kind of filters you need for any given application.

Water Filter Systems

Water Filter systems remove unwanted tastes and odours from mains water to provide clean, fresh-tasting water straight from your tap. The domestic systems such as a Watergem are compact and easy to install under a sink or small space. Commercial water filter systems are slightly different depending on the use in the kitchen or on the speciality equipment. Water filter systems come fully equipped with the kit to get you set up and tapped in to the existing water line.

Coffee Machine Filters

Water is imperative in making the perfect coffee. Normal filtration rules don’t apply to the coffee bean which needs a very special blend of minerals before it will release its full flavour. This, complete with protecting and cleaning expensive espresso machinery means coffee machine filters are another level, luckily we are well equipped to handle coffee machine water filters

Inline Water Filters

Inline filters sit directly on the water line or appliance and the water passes through the filter before reaching the tap or appliance. Commonly used in households this type of filtration is perfect for under-sink installations due to its small size.

Inline filters can reduce common problems with municipal water such as chlorine taste, odour and bacteria providing bottled water tasting water without the plastic waste. The Hydro +range of inline water filters are one of Europe’s top selling filters.

Drop In Filters

Drop-in filters are made to fit inside of a water filter housing. Housings vary depending on the use but the most common sizes are 10″ and 20″. We also stock Jumbo housings and the Watts Big Bubba housing

Fridge Filters

Fridge filters are required to filter the feed water coming through to the drinking water and ice mechanism. Most commonly found on American style fridge freezers, the size and compatibility of the filter varies depending on make/model and style of the fridge freezer.

Water Filters & Commercial Food Services

Combi ovens rely on good quality water for their steam. The chemical reaction of poor-quality water being heated to produce steam or hot water, is a main contributing factor of causing limescale which can lead to breakdowns.

Everpure Claris are one of the most trusted brands and supply catering equipment manufacturers and their service partners tailored combi oven filters.

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