Scale forms on the heating element, output falls gradually, and almost everyone blames the machine.
Why it is gradual
A scaled element transfers heat worse, so the machine takes longer to reach pressure and produces wetter steam. There is no moment of failure — just a machine that is slowly less good, until it stops being used.
Cartridge or schedule
Machines that take a descaling cartridge treat the water going in, and the cartridge is a consumable you should price before choosing the brand. Machines without one need descaling on the manual’s schedule, and that schedule assumes average hardness — in a hard area, halve the interval.
It is not only steam
Pressure washer pumps, floor washer spray jets and any heated tank all scale. On a floor washer it shows as uneven wetting; on a washer pump it shortens seal life.
What hard water also costs you
More detergent for the same result, and spotting on glass and paintwork as the water dries. Both are why people in hard-water areas end up buying deionized water for the final rinse on a car.
The questions we hear
Where do I find my water hardness?
Your water supplier publishes it by postcode, usually in °dH, °fH or mg/l calcium carbonate. It takes a couple of minutes and it is the single most useful thing you can know before buying a steam machine.
Should I use distilled water instead?
Some makers recommend it in hard-water areas and others warn against pure distilled water in their boilers. Follow the manual for your machine. A descaling cartridge is usually the more practical answer, and it is the one the manufacturer has designed for.
Last reviewed 2026-08-16
