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Water filtration system buying guide

Water filtration system buying guide

Jeremy, Construction site supervisor, Cardiff

Guide written by:

Jeremy, Construction site supervisor, Cardiff

151 guides

Whether you get your water from a mains supply, well or rainwater collector, there's only one way to improve its quality: by filtering it! There are many different types of filtration system including magnetic, active carbon, cartridge and sediment filters. Read on to find the right water filtration system for you.

Important features

  • Polyphosphate
  • Magnetic
  • Active carbon
  • Sediment
  • Cartridge
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Before we go into too much detail, it's important to bear in mind that setting up a water filter system doesn't change whether a particular source of water is considered potable (drinkable) or not. Please note that the type of filtration systems we're talking about here are not designed to make non-potable water drinkable.

That said, let's take a look at the various scenarios where you might want to install a water filter system.

Filtering drinking water

Whether your drinking water comes from the mains supply, a private well or a rainwatercollector, you might want to modify the chemical make-up of your water in order to improve its quality. You may be looking to filter your water for health reasons or to protect your home appliances or heating system. The most common reason to filter water is to eliminate or at least reduce the amount of limescale in your supply. Sediment can also be removed through filtration, provided you use the right system.

Filtering rainwater

Water collected from a rainwater collector can be used to power a toilet flush or pressure washer. In either case, the water must be cleared of any sediment and filtration is the ideal solution. Given the rising cost of water around the world, collecting rainwater is becoming an increasingly popular practice. If you plan to collect rainwater for sanitary purposes (e.g. flushing, cleaning or watering), it is essential to install a filtration system to protect your home appliances and equipment.

There are many different types of filtration systems on the market. Let's take a closer look at the most commonly used types and their main applications.

Cartridge filters

Cartridge filters do not contain any active chemicals and work on a purely mechanical basis. Designed to trap sediment, cartridge filters are great for correcting water turbidity (i.e. cloudiness).

The filtration capacity you choose will depend on the size of the material you want to capture. Simply choose the right size of cartridge; this can vary from 5 to 100µm (microns). Cartridge filters are suitable for a wide variety of applications from trapping grit in a rainwater collector to filtering out microparticles in the water before it reaches your domestic water network. Cartridge filters are often washable but must still be replaced from time to time. The most durable type of filter for this system is a wound filter.

Polyphosphate filters

This type of filtration system incorporates an active compound to limit or even eliminate limescale build-up in pipes and sanitary installations. Polyphosphate filters can either be installed at the supply point (after your water meter) or before specific appliances (your water heater, for example).

Polyphosphates use chemicals to tackle the various minerals that lead to limescale deposits. The active compound must be replaced once or twice a year, depending on your water consumption and the filter capacity. Polyphosphate filters may come in the form of cartridges.

Magnetic filters

Like polyphosphate filters, magnetic filters are designed to limit or eliminate limescale. However, they do so using electromagnetic energy. The principle is essentially the same as above except these filters work by changing the structure of the minerals that cause limescale. The advantage of magnetic filters is that they don't require any replacement parts; some don't even require a power supply. While they are less efficient than polyphosphate filters, they are discreet and can be easily set up in a kitchen.

Active carbon filters

These are the most advanced domestic water filtration systems. Designed to remove or reduce the presence of certain chemicals in your water, active carbon can also reduce turbidity to some extent. They are also able to remove certain heavy metals. If you find that the water from your taps has a strong taste of chlorine, an active carbon filter is the best solution for neutralising the taste. Installed at the water supply point, these filtration systems are often combined with pre-filters to stop the carbon elements from getting clogged up (which also helps to prolong their service life). As a general rule, you should replace your carbon about once a year.

Sediment filters

Sediment filters are also known as pre-filters. The purpose of a sediment filter is to trap sediment before it reaches your main filtration system. In most cases, the filtration capacity is around 20µm. Installed at the water supply point, just after the meter, these systems help to prevent your cartridge or active carbon filters from getting clogged up. In turn, this prolongs their service life and limits the amount of maintenance you have to carry out.

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Whatever type of filtration system you choose, remember that the aim is to improve water quality. A poorly maintained filtration system won't just fail to filter your water supply, it can even degrade the quality of your water!

If you've installed a water filtration device, be vigilant about keeping on top of maintenance.

Change your filters as required, check and replace any wear partswhenever necessary and if you are using a cartridge filter clean your cartridges on a regular basis.

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Guide written by:

Jeremy, Construction site supervisor, Cardiff, 151 guides

Jeremy, Construction site supervisor, Cardiff

Electrician by trade, I first worked in industrial estates where I installed, wired and fixed a large number of electrical installations. After this, I managed a team of electricians for this type of work. 10 years or so ago, I turned to building and construction. From the modest family home, to gyms and theatres, I have been able to coordinate, audit and organise all sorts of construction sites. For 4 years now, I am restoring and building an extension to a bungalow in the heart of the Welsh countryside. My experience in manual work and my knowledge means I am proud to be of service. Terraces, interior design, roofing, plumbing, electrics, anything goes! My wife, daughter and I, built almost everything we have from scratch! So to answer all of your questions and advise you on choosing your tools? Easy!

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