Why this basket
- Hardness facts come from the Drinking Water Inspectorate and Thames Water. Limescale is treated here as a problem for kettles, showers and dishwashers, not a health issue.
- The filter jug is the only item that changes the water itself: the DWI says ion-exchange jug filters reduce the scale that forms in kettles and the scum on hot drinks.
- Descaling intervals come from Which? for kettles and Mira for showerheads: about once a month in a hard water area.
- A plumbed-in softener is left out. It is a plumber's job, and the DWI says the drinking tap should stay unsoftened.
In the kitchen
A filter jug with ion-exchange cartridges
4.7 on Amazon · 11,830 ratings · 10K+ bought last month · #1 in Water Filter Jugs · recorded 27 Sept 2026
Always "on offer"24 of 24 days
The DWI says jug filters with an ion-exchange resin reduce temporary hardness, which means less scale in the kettle and less scum on tea. The BRITA Marella uses cartridges with ion-exchange pearls, the listing says, and comes with three cartridges of 150 litres each.
What buyers say
Buyers like
- Filtered water tastes noticeably fresher than straight from the tap(8 of 13 reviews)
- Slim enough to sit neatly in the fridge, even in the door(6 of 13 reviews)
- Flip lid for refilling and a reminder for filter changes(4 of 13 reviews)
Our summary of the 13 reviews Amazon showed on 27 Sept 2026, counted by us.
More about this pick
- Size
- about 26 x 26 x 11 cm
- Weight
- 530 g
- Material
- Plastic
- Capacity
- 2.4 litres
- In the box
- 1 X Marella Water Filter Jug, 3 X MAXTRA PRO All-In-1 Water Filter Cartridges
From the Amazon listing, recorded 27 Sept 2026. Sizes are the listing's own.
Price: we have checked it on 24 days; Amazon showed a discount of 10% or more on 24 of them, including today.
Also recommended on: someone moving into their first flat.
Replacement cartridges made for limescale
BRITA Limescale Expert cartridges (6)
4.7 on Amazon · 8,354 ratings · 10K+ bought last month · #2 in Water Filter Cartridges · recorded 27 Sept 2026
The listing says each MAXTRA PRO Limescale Expert cartridge filters up to 150 litres in 4 weeks, so six cover about 24 weeks. BRITA describes this version as 50% more effective at removing limescale than its Pure Performance cartridge, the one that comes with the jug.
What buyers say
Buyers like
- Less limescale builds up in kettles and coffee machines(4 of 13 reviews)
- Tea and water taste cleaner, without scum on top(5 of 13 reviews)
- Quick and easy to swap into the jug(4 of 13 reviews)
Our summary of the 13 reviews Amazon showed on 27 Sept 2026, counted by us.
More about this pick
- Size
- about 10 x 7.6 x 5.7 cm
- Weight
- 110 g
- Material
- Plastic
From the Amazon listing, recorded 27 Sept 2026. Sizes are the listing's own.
Price: we have checked it on 24 days; Amazon showed a discount of 10% or more on 20 of them, including today.
Descaler sachets for the kettle
Oust all-purpose descaler (18)
4.6 on Amazon · 4,080 ratings · 6K+ bought last month · #6 in De-Scalers · recorded 27 Sept 2026
Which? says to descale a kettle every month or so, following the packet instructions for a descaling powder. This Oust pack holds 18 sachets, which the listing says also suit irons, coffee machines and shower heads.
What buyers say
Buyers like
- Clears limescale from kettles and is easy to use(9 of 13 reviews)
- Also does coffee machines, for far less than branded descalers(2 of 13 reviews)
- No taste or smell left once rinsed and reboiled(3 of 13 reviews)
Watch out for
- Heavy build-up can need a second sachet or a longer soak(4 of 13 reviews)
Our summary of the 13 reviews Amazon showed on 27 Sept 2026, counted by us.
More about this pick
Price: we have checked it on 24 days; Amazon showed a discount of 10% or more on 0 of them.
A steel scale collector for the kettle
4.1 on Amazon · 171 ratings · 50+ bought last month · #12 in Electric Kettle Accessories · recorded 27 Sept 2026
Thames Water suggests a steel scale collector in the kettle, and emptying the kettle when it is not in use. Lakeland's kettle protector is stainless steel and suits electric and stovetop kettles, per the listing.
What buyers say
Buyers like
- Cuts down the scale and flakes that collect in the kettle(7 of 12 reviews)
Watch out for
- Slows scale down rather than stopping it altogether(3 of 12 reviews)
- Some see no difference at all in very hard water(3 of 12 reviews)
Our summary of the 12 reviews Amazon showed on 27 Sept 2026, counted by us.
More about this pick
- Size
- about 2.5 x 2.5 x 2.5 cm
- Weight
- 20 g
- Material
- Stainless Steel
- Capacity
- 1.5 litres
- In the box
- 1 x Lakeland Kettle Protector
- Care
- Hand wash or dishwasher-safe (unconfirmed)
From the Amazon listing, recorded 27 Sept 2026. Sizes are the listing's own.
Dishwasher salt for the softener unit
4.7 on Amazon · 6,856 ratings · 20K+ bought last month · #1 in Dishwasher Salt · recorded 27 Sept 2026
Which? says dishwasher salt softens the water so detergent works better, and stops limescale clouding glasses and clogging the machine. Set the hardness level from your water company's figure and the dishwasher manual. Finish salt comes in a 2 kg bag, per the listing.
What buyers say
Buyers like
- Glasses and dishes come out clear, without spots or film(8 of 13 reviews)
- Keeps limescale from building up inside the machine(5 of 13 reviews)
- A 2kg bag lasts for several refills(4 of 13 reviews)
Our summary of the 13 reviews Amazon showed on 27 Sept 2026, counted by us.
More about this pick
Price: we have checked it on 23 days; Amazon showed a discount of 10% or more on 0 of them.
In the bathroom
Citric acid to soak the showerhead
4.7 on Amazon · 4,968 ratings · 2K+ bought last month · #16 in De-Scalers · recorded 27 Sept 2026
Mira says to descale a showerhead about once a month in a hard water area. Which? prefers citric acid to vinegar: two tablespoons in a litre of hot, not boiling, water, with the head soaked for about an hour. This is 1 kg of food-grade citric acid, per the listing.
What buyers say
Buyers like
- Clears limescale from kettles, taps and showerheads(3 of 8 reviews)
- Good value, and one bag lasts a long time(3 of 8 reviews)
- Handy for other jobs too, from baking to home-made cleaners(4 of 8 reviews)
Our summary of the 8 reviews Amazon showed on 27 Sept 2026, counted by us.
More about this pick
A limescale spray for taps, tiles and screens
4.7 on Amazon · 496 ratings · 10K+ bought last month · #1 in De-Scalers · recorded 27 Sept 2026
For taps and tiles, Mira suggests white vinegar or lemon juice first and a specialist limescale cleaner for stubborn scale, with gloves on. Mira also warns that abrasive chemicals can damage the finish on fittings, so follow the label. Viakal is a limescale remover spray, 1,050 ml per the listing.
What buyers say
Buyers like
- Shifts limescale from taps and shower glass(6 of 8 reviews)
- Spray on, leave it a while, then wipe off with little scrubbing(3 of 8 reviews)
- The big bottle lasts a long while(3 of 8 reviews)
Our summary of the 8 reviews Amazon showed on 27 Sept 2026, counted by us.
More about this pick
Price: we have checked it on 24 days; Amazon showed a discount of 10% or more on 0 of them.
Also recommended on: moving-out cleaning.
Can wait
- Water hardness test strips. Your water company publishes the figure for your area, and the DWI says to ask the company directly for an accurate one.
- A plumbed-in water softener. It needs a plumber, and the DWI and Thames Water both say to keep a separate unsoftened tap for drinking and cooking.
Skip it
- SkipA softener on the drinking tapThe DWI says not to soften the kitchen tap used for drinking and cooking, and South East Water says softeners can significantly increase sodium levels in water.
- SkipTable salt in the dishwasherBosch says table, sea or kosher salt can increase water hardness and damage the appliance; Which? says table salt contains anti-caking agents.
Quick questions
Is hard water safe to drink?
Yes. Thames Water says hard water is not considered harmful, and the DWI notes that UK drinking water rules set no standard for hardness. The trouble is limescale: tide marks on sinks and baths, scum on tea and scale on kettle elements.
How do I find out how hard my water is?
Ask your water company; Which? says the figure is usually on its website, often in mmol/l. The DWI says the company's figure is more accurate than a regional map because hardness varies locally. Use it to set your dishwasher's hardness level from the manual.
How often should I descale the kettle?
Every month or so, says Which?, and more often with a glass kettle in a hard water area. Thames Water suggests emptying the kettle when you are not using it and putting a steel scale collector inside to slow the build-up.
Do I need dishwasher salt if my tablets contain salt?
Yes, for the best results. Which? says all-in-one tablets contain some salt but still recommends topping up with dishwasher salt. Most machines have a salt light; without one, Which? suggests refilling about once a month.
Should I fit a water softener?
Only with a separate unsoftened tap for drinking and cooking, say the DWI and Thames Water. South East Water says softeners can significantly increase sodium levels in water. The DWI suggests a qualified plumber from a recognised trade association.
Sources: Drinking Water Inspectorate: Water hardness (checked 26 September 2026); Thames Water: Hard water (checked 26 September 2026); South East Water: Water hardness (checked 26 September 2026); Which?: How to descale a kettle (checked 26 September 2026); Which?: Dishwasher salt and rinse aid explained (checked 26 September 2026); Bosch UK: What does dishwasher salt do? (checked 26 September 2026); Which?: How to descale a shower head (checked 26 September 2026); Mira Showers: How to clean and descale your shower head (checked 26 September 2026); Mira Showers: How to remove limescale from showers and taps (checked 26 September 2026).
