BWT Water Softener Review (WS555, WS455, WS355)

Welcome to a new Water Filter Geek deep dive, and on this occasion it’s a BWT Water Softener Review. Specifically, the 3 main models they offer – the WS555, WS455 and the WS355.

BWT term this WS range as their luxury range. We’ll take a look at whether the softeners live up to that billing.

We’ll analyse what qualities these softeners have, their weaknesses, and most importantly we’ll let you know exactly how effective they can fix your hard water problems.

By the end of this review, you’ll know how well they actually soften your water, how much upkeep and maintenance is required. All in all, you’ll get to grips with whether water softeners are worth the money or not. Check out the specs and pricing on Amazon, of the WS555, the WS455, and the WS355.

bwt water softener review

Introducing the BWT Water Softener Review

Here’s what the three models look like and their specifications:




DIMENSIONS60.2 x 48 x 27cm53.2 x 48 x 27cm60.2 x 48 x 27cm
FOR HOUSEHOLD SIZEUp to 6 peopleUp to 4 peopleUp to 6 people

Let’s take a look at what we liked, and what we didn’t like, in detail.

The Good Things About The BWT Water Softeners

The benefits of the WS555, WS455, WS355 models are the following:

They really work (ie. they really soften your water)

Surely that’s just the bare minimum, right? Well, yes but some people are sceptical on this point. They’ve had such consistent, annoying issues with hard water that they’ve been somehow persuaded that it can’t be fixed.

Rest easy on that score. The BWT water softeners are the top sellers on the UK market and there’s a reason for that. They do work, and people are very often surprised that they work pretty much immediately.

So, you will get the benefits of newly softened water. People have found these to be the following:

  • Smoother, softer, less irritated skin (and no more worsening of skin conditions) & healthier, brighter hair
  • Laundry that is softer, brighter and keeps its colour longer
  • Energy cost savings due to cleaner, clearer pipes and central heating systems (hard water causes limescale deposit damage in valves and pipes)
  • Longer lasting appliances, for example washing machines, kettles and dishwashers (since they no longer have regular scum deposits developing).
  • Cost savings on detergents, cleaning agents, shampoo, soap etc. That’s because soft water allows far better lathering, and using up to 50% less than you were before.

Curious as to how water softeners work?

More accountability, ease-of-contact, service as BWT are a European Manufacturer

BWT are headquartered in Mondsee, Austria. They were established in 1823, so they’ve been around effectively forever. Their sole business is the manufacture of water treatment systems; they can certainly be considered experts in this field.

They’re trusted enough to supply plenty of huge global companies, and even sponsor the Alpine Formula One team.

They have a UK base, with 130 staff. As a result, their after-sales care is excellent, and well-renowned, with the ability to give you truly local advice and expertise.

Production of their water treatment systems, like water softeners, takes place in Austria, Germany, Switzerland and France. European production, particularly in the likes of Germany and Switzerland is extremely high regulated and of a very high standard, generally. So the build quality of BWT water softeners are excellent.

Fits in most houses kitchen cupboard

The BWT WS555 is the biggest selling model in the UK market.


Because it has a high capacity of water (14 Litres), and yet still fits into most kitchen cupboards.

It provides water for up to 6 people, based on average water usage. A lot of people with a household of 3 or 4 people still choose this model so that they’re comfortably covered with enough water. For example, as younger children grow up and become adults, it’s inevitable that water usage will increase over time.

The WS555 is in the goldilocks zone, as it’s the largest capacity of water for a water softener that can still fit into your cupboard.

Those dimensions are:

60.2 x 48 x 27cm

The WS355 model shares these dimensions.

The WS455 model is smaller. It’s capacity is 10 Litres.

It’s designed for 4 people, and in reality you’ll find it’s people with households of 1, 2 or 3 people that purchase this model, so they have comfortably enough water.

It’s dimensions are:

53.2 x 48 x 27cm

Therefore, as you can see it has the same width and depth, but is 7cm shorter in height.

You can set and forget (to the exact water softness you need)

These BWT models are the new generation of smart water softeners.

What does that mean?

It has smart water monitoring. An ECU (Electronic Control Unit) allows you to choose the level of water hardness you prefer. In the past, it was a relative crapshoot, where households with just a little hard water may receive the same treatment as one with extremely hard water. The end results would vary a lot.

But these BWT softeners will automatically give you exactly the softness of water that your home needs, that you choose yourself.

You can also choose the regeneration time. (Regeneration is when the unit effectively cleans itself). You’re not at mercy to the machine! Some older water softeners on the market will choose when to do so and you may be unable to get softened water at that time. You choose when you want it to regenerate. It’s automatically set to 2am but you can change it easily.

This smart monitoring also means that it uses water more efficiently. Thus, there is less waste water, which is better for the environment.

Weaknesses of the BWT Water Softeners

What didn’t we like about these softeners?

Too big for under the sink in many cases

As mentioned, the WS555 has big capacity, comfortably enough for 3 or 4 people, and even up to 6 people. And can fit into kitchen cupboards.

Under the sink, though? Well, to know that that you’ll need to check the space. Sometimes pipes and valves mean that there’s not enough space to put it there.

Bear in mind though, that it’s fine to put it in other places.

The lid falls off too easily

There’s a plastic lid on top of the unit, and it comes off very easily.

It doesn’t like a major issue, but when it comes off it can take cables with it. This can potentially damage the cables and wires.

It’s surprising then that BWT don’t simply out some clips to keep the lid on. Perhaps they’ll add that soon.

In the meantime, some people are attaching it more strongly using Blu Tack or strong tape.

Anything else we need to know about these softeners?

They’re WRAS approved.

WRAS is the Water Regulations Advisory Scheme.

If you get an expensive water treatment unit like this, you really want it to be WRAS approved.

It means it’s been really rigorously tested, according to the UK Water Supply (Water Fittings) Regulations (and Scottish Bylaws).

This scheme gives the highest possible assurance that the product will not contaminate or waste your water.

5 Year Warranty

It’s a 5 year parts warranty, and 2 year labour warranty.

So if any parts act up within 5 years you’re covered in terms of their cost. And, if there’s any work that is required within 2 years, BWT will cover the labour cost.

The WS355 and the WS555 are identical except for…

1) The WS355 has 15mm connection hoses, whereas the WS555 has 22mm connection hoses.

They’re both for 6 people, both 14 Litres capacity.

The WS555, with 22mm connection, therefore has hi-flow capabilities. And suitable for combination boilers.

The WS455 also has 22mm connection hoses, and is suitable for combination boilers.

2) With the WS555 and WS455, you can use tablet salt or block salt. With the WS355, you can only use tablet salt.

3) The WS555 uses less salt (approx. 0.6kg-2kg) than the WS355 (approx. 1.2kg-2.4kg).

Have a big household?

There’s also an 8-person softener, the WS655, and a 10-person softener, the WS755.

As you may expect these units are bigger. They certainly wouldn’t fit into a kitchen cupboard – you’d have to find room elsewhere.

Here’s where to check them out, on Amazon:

The WS555

The WS455

The WS355.

Summing Up the BWT Water Softener Review

The BWT Water Softeners are, we feel, the best on the market.

They’re the water softener that are guaranteed to give you softened water, the most likely units to fix your hard water problems.

And crucially, they’ll give you the exact softness of water that you set it to.

There are a few downsides. These models probably won’t fit under your sink (though they will fit on other kitchen cupboards). But remember that all softeners on the market are as big, if not bigger. So this applies to them all.

And that plastic lid issue, you’ll have to take some pre-emptive action on that.

And price? Well, as recently as 5-10 years ago, you’d likely need to pay £1000 plus for a softener with this capacity and quality. Now, the price for a water softener system in the UK is a lot less.

All in all, it’s certainly a high quality product, from an extremely solid manufacturer, and with excellent after-sales service. For these reasons, we have ranked the BWT (and particularly the WS555 model) as the No.1 water softener on the UK market.

If the WS555 is the right one for you, here’s the best place to get it, on Amazon.

And the WS455 is here.

And check out the WS355 on Amazon, here.