Is a water softener worth it in a London home?

Large parts of London have hard water, meaning it carries a high level of dissolved calcium and magnesium. It is safe to drink and use, but it leaves limescale behind on anything it touches repeatedly — kettles, shower screens, taps, and the inside of pipework and appliances where you cannot see it.

What limescale actually costs you

Scale builds up inside a boiler's heat exchanger and a washing machine's heating element, making both work harder to heat the same amount of water. Over a few years that shows up as higher running costs and, eventually, appliances failing earlier than they should. It is also the chalky residue on taps, shower glass and kettles that no amount of cleaning quite keeps ahead of.

What a softener changes

A water softener exchanges the calcium and magnesium in the water for sodium, using a resin that is periodically recharged with salt. Softened water does not scale up appliances or surfaces the way hard water does, and most people notice a difference in how soap and shampoo lather, since hard water needs more of both to get the same result.

What it does not change

• It does not filter the water or improve taste on its own — that is a separate job, done by filtration rather than softening.
• It typically softens the whole house, not just drinking water, via a unit fitted where the mains supply enters the property.
• It needs salt topped up periodically to keep working.

Whether it is worth it comes down to how hard your specific supply is and how much scale you are already seeing. In most of London the answer leans yes, particularly if you are already replacing a boiler or a shower and can factor the softener in at the same time.

Hard water is also behind a lot of combi boiler trouble, from scaled heat exchangers to lukewarm hot water. Our guide to no hot water explains the signs, and a yearly boiler service is the time to have it checked. For fitting and servicing other kit, see appliance and fixture plumbing.