. Water Softener Buyers Guide | How to Choose a Water Softener

Water Softener Buyers Guide

Living with hard water and limescale can cause serious problems in the home – both in the short and long term. The only way to get rid of hard water for good, is to have a water softener installed.

But where should you start? What size water softener do you need? What is the best brand? How is the system installed? How much should you be paying for a water softener? And is it even worth the cost? 

This water softener buyers guide is designed to answer all of your questions. If you need to jump straight a specific question– click a link below. If you need any more information - click our online chat to talk to an expert now.

What damages can hard water cause?

  • Limescale & white scale deposits: on your surfaces, fixtures & fittings.
  • High energy bills & poor heating: limescale coats the inside of your pipes and heating system – this reduces heating & water efficiency and means more energy is needed to heat your home and hot water.
  • Blocked pipes, taps & showerheads: Limescale blocks taps and shower heads, leaving a crusty green or white coating and reduced water flow. Eventually, this damage will require costly replacements.
  • Damaged & Broken Appliances: limescale can cause major damage to washing machines, kettles and dishwashers. Hard water can reduce the lifespan of these appliances by up to 50%.
  • Eczema & dry skin: the minerals in hard water damages your skin barrier, leaving it more sensitive. It’s a known cause of eczema, dry skin and even acne and greasy hair.
  • Expensive cleaning products: cleaning limescale is a constant job. If you don’t clean your kitchen and bathroom straight away after using the water – you’ll risk permanent stains on your surfaces, fixtures and fittings. This means spending hours cleaning limescale stains, and money on expensive cleaning products, descalers and even more water for the cleaning.
  • Boiler damages and issues: limescale and hard water causes permanent damage inside your boiler. This can lead to expensive repairs and call out fees, or even full a replacement.
limescale damagfe shower head
limescale damage in the home

How does a water softener work?

A water softener works by filtering out hard minerals from your main water supply. It does this using a process called reverse osmosis.

Inside of a water softener there is an internal resin, which contains small nano beads. This resin extracts hard calcium and magnesium ions from your water and hold them on its surface.

Once the resin is full of minerals and saturated, the system uses a brine solution (salt water) to clean the resin and flush away the waste minerals. The system makes this solution in its brine tank, using salt blocks or tablet pellets. The waste minerals are then flushed down a drain pipe and drained away. This is the water softener regeneration process.

What are the benefits of a water softener?

To put it simply, if you have limescale and hard water problems – you need a water softener. If you don’t have hard water, then you don’t! A water softener is a home investment that protects your home from expensive long damage. Not only that, but you’ll experience tons of other benefits including:

  • No more limescale or white stains: a water softener prevents scale stains and also slowly removes pre-existing limescale.
  • Reduced energy bills by 20-64%: by slowly removing limescale from inside your heating system, soft water actually increases heating efficiency and lowers bills. 
  • Protects & prolongs appliances: preventing damage & increasing the lifespan of appliances by 50%.
  • Protects your boiler from costly damage: soft water is great for your boiler and prevents permanent limescale damage.
  • Unblocks pipes, taps & showerheads: soft water protects fixtures, fittings & water pressure in your home.
  • Naturally cures Eczema, Dry Skin & Hair: hard water is a big cause of dry skin and eczema. It can also cause frizzy and greasy hair. Soft water naturally treats eczema and leaves your hair shiny & soft.
  • Reduces cleaning & laundry costs: With soft water you can clean less, saving on cleaning products and water. You can also reduce the amount of showering products you use.
  • Cleaner laundry: soft water reacts with washing powders and soaps in a positive way, producing a lather. This means a little can go a long way and you can reduce the amount of washing powder you use by up to 50%. You’ll find your clothes appear much cleaner, and stains are removed more effectively.
limescale free taps
limescale on washin machine

What size water softener do I need? 

The size of the system you need depends on:

  • How many bathrooms your home has.
  • The number of occupants in your home.
  • What boiler and heating system your home uses.

Generally, homes with 2+ bathrooms require a twin tank system. Good quality brands, produce twin tank systems that are small enough to fit underneath your kitchen sink.

Homes with 4+ bathrooms or many occupants, will require a larger water softener. Larger water softeners require more space as they are a lot bigger. A water softener should be installed as close to your stop tap as possible.

Single tank systems are generally only suited for 1 bathroom flats or very small homes with a single occupant.

What’s the difference between a single and twin tank system? 

A single tank system has one resin tank, whereas a twin tank has two independent tanks. This means, when the internal resin becomes saturated, a single tank system has to shut off the supply of soft water, while it regenerates & cleans itself. You may not be able to control when this is. A single tank water softener also has a lower flow rate and less capacity than a twin tank.

Twin tank systems are generally more efficient, with higher flow rates. They provide a 24/7 soft water supply – when one tank becomes saturated, the system will switch to the second tank as the regeneration process occurs.

One very important factor to consider when choosing a system is – you often can’t drink the water produced by a single tank water softener. This is due to the quality of the resin inside. As a result, you will need to isolate a hard water drinking feed or install a drinking water system, if you choose to opt for a cheaper single tank.

Which is best - electric vs non-electric water softener?

Electric systems are less efficient. They have much higher running costs because they require electricity and use more salt & water. They need to be manually set to regenerate at certain times. This means the system may regenerate when it doesn’t really need to – using more water and salt.

Not only that, but due to requiring electricity, they need a constant power source which can cause circuiting and power cut issues. You’ll also need to make sure you have the system serviced to be safe for use – which means additional call out fees every year. You also cannot drink the water produced due to its sodium contents.

Non-electric systems are often more up to date in terms of technology and are the most efficient models you can get. They don’t require any electricity and are automatic. This means they don’t have timers or controls and these systems automatically measure your water usage – meaning they regenerate only when the have to. With high quality machines/brands the water is also drinkable (**see more info below). With a non-electric system, you may pay more initially, but the running costs and extended lifespan, makes up for this in a matter of months.


non electric water softener
block salt water softener


Can I drink softened water/ Is softened water safe to drink?

Soft water from a single tank machine often contains too much sodium to drink.

Twin tank models from top Harvey & Kinetico, produce water that is generally deemed safe to drink and within the government sodium recommendations. However, there are some exceptions. Soft water is not suitable to drink if you are on a medically prescribed low sodium diet or if you are bottle feeding a small infant. In these cases, you may need to isolate a hard water feed or install a drinking water system. 

What are the important technical details to look out for?

The type of system:

Check if the system is twin tank or single tank. Twin tank systems are suited for homes with 2+ bathrooms. They are more expensive - but are generally more efficient. You should also consider if you need a HE or HF system. A HF is required for high flow and combi boilers. A HE can be suitable for low flow gravity fed systems. 

The flow rate:

The flow rate is the maximum amount of water that can pass through the system at one time. It should be 40-60L/min for a standard home. A low flow rate, may result in a drop in the flow of water to kitchen & bathroom outlets. 

The efficiency, salt & water usage:

Buying an efficient system is important. The efficiency determines the overall running costs. You should look at and compare: the regeneration time and how much salt and water the system uses per regeneration.

The warranty:

Price and warranty are key indicators of quality.

A third party certification:

Any system you purchase should have a third party WRAS certification. 

Is a warranty important?

Yes! Warranty are key indicators of quality. Look out for cheap systems and always look for a long warranty. Buying a low-cost machine for under £1,000 - may actually cost you more in the long run, to run or replace when damaged.

Why do I need salt? What’s the difference between block and tablet salt?

A water softener needs salt to work. Without salt – you won’t have soft water. Look out for cheap eddy descalers or systems which do not use salt. These are not water softeners and they cannot effectively remove hard minerals from your water.

Block salt is used in most standard systems. Blocks are easy to use and replace. Tablet salt tends to be used in larger water softeners, because they have a bigger storage and brine tank and therefore, can hold large amounts of tablet salt. 

How Much is Salt and whwre can I buy it?

Block salt should come in packs of 2 x 4kg blocks. These packs are priced between £6-£8. Tablet salt, usually comes in 25kg bags and is around £15-17 per bag. You can buy salt direct from Harvey or online from amazon or even ebay.

The amount of salt your system uses also depends on how much water you use and the number of occupants. As a rule of thumb, salt usage is generally 1 block per person per month.

block salt water softener
water softener buyers guide

What are the running and maintenance costs of a water softener?

A non-electric water softener does not require electricity, therefore, no additional energy costs are required. The main running cost of a water softener is salt - which needs to be regularly topped up. A constant supply of salt is required in order for the softener to work. 

That's why it is important to check the salt efficiency and water consumption of any system. A low salt efficiency will result in replacing the salt more often - which will cost you more in the long run.

An efficient system such as the Harvey TwinTec S4, will use 300-400g of salt and 17-23L of water per regeneration.

How is a water softener installed? Can it be installed outside?

A water softener is plumbed to intersect your mains water suppy. It is generally installed by a local plumber and installed next to the stop tap – which is usually under the kitchen sink. It is important to make sure you have enough space. In cases where there is little space under the sink, a water softener can be installed outdoors. When choosing this option, you must also buy an external cabinet to protect the system.

Larger water softeners for homes with 4+ bathrooms, are much larger and often have two components. These systems are usually installed in a plant room, utility room or garage.

How much should I be paying for a water softener? Is a water softener worth the cost?

Initially, a water softener can seem like an expensive home investment at around £1300 - £1800. But did you know - a good quality system can last 10-20 years? And soft water can actually save over £400 per year!

Soft water can result in savings on household bills by:

  • Reducing energy bills by 20-64%.
  • Increasing the lifetime of home appliances by up to 50%, preventing costly damages & replacements.
  • Reducing time & money spent cleaning - buy less cleaning products & forget expensive descalers.
  • Soft water requires 50% less washing powder.
  • Soft water requires less shampoo & showering products.
  • Results in you using less water overall in the home. 

With all the additional soft water benefits, a good quality water softener literally pays for itself. It is however, important to buy a good brand an efficient model. Cheap systems and electric systems can end up costing you more in the long run.

What are the best water softener brands?

The two best brands of water softener are Harvey & Kinetico. Both brands have been around the longest and are the most popular in the UK. Harvey innovated the twin tank design and Kinetico invented the non-electric water softener.

These brands are hard to find online as they are sold through an exclusive offline dealer network. This means only specific distributors are able to sell certain models.

Why Are They the Best?

Harvey & Kinetico models provide the best quality systems that can last 10-20 years. Their softeners hold third party certification, to guarantee reliability and durability.

Most of their systems also come with 10-year warranties.

They can cost a little more initially but they last 2x as long as softeners produced by other brands and have the lowest running costs - meaning over the years they pay for themselves.

Harvey Vs Kinetico

Many people struggle to choose between Harvey & Kinetico. The Harvey TwinTec S4 has the best specification of any domestic softener. On the other hand, Kinetico is renowned for quality and systems that can even last over 20 years. Kinetico products tend to be slightly more expensive. Both brands are very popular and a reliable and cost-effective choice. They are great long term home investments, providing exceptional customer service.

The best model for 2 & 3 bathroom homes

The Harvey TwinTec S4


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Harvey Water Softener
Non-electric & twin tank design.
The most efficient system on the market, low salt & water consumption.
High flow rate of 56L/min - no pressure drop. 10 year warranty. 

    The Kinetico Premier Compact


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    kinetico water softener
    Non-electric & Twin tank design.
    Very efficient system, low salt & water consumption. High flow rate of 51L/min - no pressure drop.
    10 year warranty.
    Renowned for quality & lasting a lifetime.
    For 4+ bathroom homes.

    Harvey TwinTec XL2


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    harvey xl2
    Mega high flow rate of 80L/min. Suitable for 4-8 bathrooms.
    Non-electric & twin tank design.
    High salt storage - holds 6 blocks.
    10 year warranty.


      Kinetico Premier Plus


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      kinetico premier plus
      Non-electric & Twin tank design.
      Very efficient system, low salt & water consumption.
      High flow rate - suitable for 4 bathroom homes.
      10 year warranty. Renowned for quality. 

        The Harvey big blue


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        Harvey big blue
        High flow rate of 80L/min.
        Non-electric & twin tank design.
        Tablet salt - efficient salt consumption.
        Suitable for very large homes & small businesses.
        10-year warranty. 

          Need more help? 

          Call us now on 02031486773 for free advice & exclusive discount codes. Get the best price online, from the UK's biggest online water softener supplier.

          Contact us online: www.newatersofteners.co.uk

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