How to buy the best water softener

If you're struggling with hard water that's staining your appliances or ruining the taste of your drinking water, a water softener could be a savvy investment. But what does it actually do and how much do you need to spend? Our expert guide answers your key questions.

A reliable water softener can remove damaging minerals effectively from your water supply. So you'll end up spending less to fix or clean the home appliances you use most often.

Below, we explain how water softeners work, how much they cost and where you can buy them. Plus, we have details on which features to look out for when picking a new model.

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What is a water softener?

Water softeners are devices designed to tackle the issue of hard water, where water has a particularly high mineral content (usually calcium and magnesium).

Hard water can be a problem in homes, as minerals contained within the water can create scale and form deposits that clog your pipes. To tackle the issue, a water softener will replace those minerals with softer alternatives (sodium and potassium) through a process known as ion exchange.

The machine will also attract and hold on to any positively charged ions, such as iron (which can cause stains).

How does a water softener work?

Water softeners are made up of a mineral tank and a brine tank. They attach to your mains water supply, which means water is softened before it reaches the tap. You'll need to install a water softener at an easy access point – under the kitchen sink is ideal.

The mineral tank contains resin beads and this is where the ion exchange takes place. When the system needs to regenerate, heavy brine solution is drawn from the brine tank and passed through the resin in the mineral tank. The brine tank needs to be manually refilled with salt.

Water softeners can either be time-controlled or metered. Timed models are more basic and generally the cheaper option. They run on a set schedule, which is based on the hardness of the water supply and capacity, as well as the number of people living in the property.

However, timed models can cost more to run in the long term. If the water usage is lower than the calculated amount, it can lead to wasted softened water capacity. If water usage is higher than calculated, water may not be softened sufficiently.

Metered water softeners will regenerate when a pre-set volume of water has been used up – this means there is less waste.

Installing a water softener

When installing a water softener, you'll want to position the device at the mains water supply. Usually, the machine will sit underneath your kitchen sink and attach to pipes from there. You might also have access to your water supply at another spot in the house – your garage, for example.

Installing a water softener yourself can prove complicated if you're not experienced with plumbing. If you want a professional to deal with installation, enter your postcode in the tool below, or visit the Which? Trusted Traders website.

Problems caused by hard water

What is hard water? Water that contains high levels of minerals that cause scaling.

If your home has hard water, you might find that your water has an unusual taste or smell. Dark stains caused by iron can build up in your toilet, and minerals in the water can make it harder to lather in the shower or bath.

Softer water reduces the risk of limescale, plus it lengthens the lifespan of appliances that use hot water – showers, washing machines and dishwashers, for example. And you won't have to spend as much money on cleaning products to remove limescale and tackle stains.

Discover the best bathroom cleaning sprays for shifting limescale. Our tests also reveal the best kitchen cleaning sprays and all-purpose cleaning sprays 

How hard is my water?

There are a number of websites you can use if you want to check your local area's water supply. One such site is Aqua Cure. Simply enter your postcode and it will tell you if you live in a hard-water area.

Hard water is measured in parts per million (ppm) and defined by the Aqua Cure website into these categories:

• Soft water – 0-50ppm
• Hard water – 201-275ppm

According to Aqua Cure, hard-water areas are generally found in the South East and parts of Ireland.

Water softener features to look out for

• Size – before you buy your water softener, make sure you know how much space you have available. Measure underneath your kitchen sink and then check the machine's dimensions on the manufacturer's website.
• Salt type – once you've settled on a water softener, check what type of salt the manufacturer recommends. Some machines use salt tablets, while others use larger chunks of block salt.
• Digital display – take some time to familiarise yourself with the machine's built-in display. This usually has a clock, along with information on flow rate and salt level.
• Smartphone app – some water softeners partner with a mobile app, where you can access additional information. For example, water softener brand Harvey has its own app called myHarvey, which guides you through the setup process.

If you're looking to make additional upgrades to your kitchen, check in with our guide on the best kitchen appliances.

How much does a water softener cost?

Prices will vary depending on the size of the water softener you're looking at – you can expect to spend anywhere between £300 and £1,500. Popular water softener brands include Aqua Cure, BWT, Harvey, Kinetico Kube and Water2Buy.

While the initial cost may seem high, the long-term benefits of owning a water softener will hopefully mean you'll save on repair and cleaning costs.

To ensure the water softener can continue doing its job effectively, you'll need to add salt tablets to the machine when it runs low – leave it no longer than two months between refills. The time between refills will vary depending on how much water your household uses. Note that some water softeners have a salt level indicator that alerts you when it's time to restock.

You should expect to spend between £20 to £30 on a 25kg bag of salt tablets.

Where to buy a water softener

If you're shopping for a new water softener, make sure you’re handing over your money to a reputable seller. Check the retailer's returns policy and also have a look at customer reviews. Our advice guide on online shopping has more details.

Popular retailers that stock water softeners include:

• Screwfix – sells water softeners made by BWT. Typical prices range from £500 up to £1,000.
• Amazon – stocks a range of water softeners from big-name brands including BWT, Kinetico and Water2Buy. Expect to spend anywhere between £300 and £600.
• Homebase – currently sells water softeners from Kube. Prices start at around £680 and rise to around £900.
• Water2Buy – lists its full range of machines online. Its 'popular' models cost £500-600.

Find out which retailers are rated highly by Which? members with our expert guide to the best and worst shops.

Other ways to deal with hard water

Aside from investing in a water softener, there are several other ways to deal with the negative impact of hard water.

To help your appliances last longer, get into the habit of descaling them regularly. See our advice guide on how to descale your kettle and make sure your dishwasher salt is topped up. You can also experiment with water softening products in your washing machine.

Alternatively, you can try fitting a water filter to your taps, as this makes it easier to get lather from soap. A showerhead filter could also be beneficial, as this filters out contaminants and limits limescale.

If hard water and limescale have wreaked havoc on your appliances and you're in the market for new ones, check our guide to the best kitchen appliances.

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