How hard water actually shows up in boilers (in real homes)
The call is usually the same vibe: “Boiler’s fine… but hot water goes weird” or “pressure keeps dropping” or
“it’s making a kettle noise when it runs.” And half the time, the kitchen tap has that chalky ring around it too.
Limescale doesn’t always kill a boiler overnight — it’s sneakier than that. It narrows waterways, reduces heat transfer,
and forces parts to work harder. In combis, you often feel it as hot water performance dipping, or the boiler cycling on/off more than it should.
Over time, that can nudge your new boiler prices conversation from “sometime next year” to “this week, please”.
If you’re already weighing the new boiler cost or the boiler fitted cost, protecting the system properly is one of the easiest ways
to avoid paying twice. And if you’re literally comparing boiler change prices right now, this is the kind of detail that separates a clean install
from a “works for now” install.
A real London moment: the “kettle noise” phone call
We had one around the Forest Gate / Manor Park edge — small terrace, combi in a kitchen cupboard.
Customer said the boiler sounded like a kettle whenever hot water ran, and the shower would go hot… then cooler… then hot again.
Classic “it’s fine, but it’s not fine”.
We checked the obvious first (pressure, basic settings, flow), then looked at protection and system history.
The heating side had no filter and the system water looked tired. On the hot water side, you could see scale symptoms building.
We didn’t jump straight to “new boiler prices” — we stabilised what could be stabilised, then explained what protection would stop it coming back.
That’s the pattern: hard water rarely arrives alone. It teams up with rushed installs, missing protection, and systems that haven’t been cleaned properly.
If you want to understand the “fitted” side of costs, this page is useful:
boiler fitted cost in London.
What people actually care about after the job
Most customers don’t say “thank you for correct inhibitor levels” (fair).
They say: you turned up, you were honest, you fixed it fast, and you didn’t leave a mess.
“My boiler went wrong… Abdul and his team came and fitted a new one. They worked without taking a break, cleaned up when they were done.”
Alison Louis
“Excellent plumbing service! Always punctual, professional, and true to their quote — highly recommended!”
Elimelech Halberstam
“Great service prompt and efficient. Fitted a new boiler at a very competitive price also took away old boiler and all other waste.”
Grant Hodges (Local Guide)
If you’re in the middle of comparing cost of installing a new boiler quotes and one feels “too tidy”, call us.
We’ll tell you what’s missing — and if you’ve got a good quote already, we’ll even say that.
Hard water & boiler limescale FAQs
Is London water really bad for boilers?
London is classed as a hard water area, which means limescale build-up is a genuine issue over time. The good news is
you can protect a boiler properly with the right setup — it doesn’t have to be a constant problem.
Will a scale reducer fix my boiler problems?
Sometimes it helps, sometimes it’s only part of the story. If the heating circuit is dirty (sludge/debris), or the boiler wasn’t commissioned well,
a scale solution alone won’t fix underlying issues. We usually look at the whole system before recommending anything.
Does limescale affect combi boilers more?
Combi boilers can show hot water symptoms more obviously because they’re producing hot water on demand. If waterways narrow or heat transfer drops,
you can notice temperature swings or reduced performance sooner.
Do I need a power flush because of hard water?
Hard water and sludge aren’t the same thing. A power flush is about cleaning the heating circuit (sludge/debris).
Some systems need it, some don’t. This page explains it properly:
do I need a power flush with a new boiler?
How do I get a quote for protection or a new install?
Call +44 7727 154 746 for a quick chat, or send photos using
our contact page.
If you’re comparing the boiler fitted cost or boiler change prices, we’ll help you make sense of what’s included.