Limescale in your mixer tap: clean it or replace it?

Does this ring a bell?

White crusts around the spout, a handle that moves stiffer than it used to, and a water stream that's no longer even. Limescale is the most common cause of "old tap" complaints — but not every case calls for replacement.

Where's the difference?

Limescale settles in two places: visibly on the outside (spout, aerator) and invisibly inside (cartridge, mixing mechanism). Outer limescale is almost always solved by cleaning. Inner limescale is the trickier story.

Test 1: the vinegar test for the aerator

Unscrew the aerator, soak it for 30 minutes in a bowl of (warmed) cleaning vinegar, rinse and brush the holes clean with an old toothbrush. Does the water stream flow evenly again? Then that was the only culprit.

Test 2: the operation test for the cartridge

Does the handle move stiffly despite a clean aerator? Then the limescale is inside the cartridge, between the moving discs. Cleaning rarely helps structurally here — the discs are often already damaged by pitting and scratches from limescale crystals.

Rule of thumb: clean or replace?

Cleaning is enough for: build-up on the spout, a clogged aerator, scale on the tap's surface.
Replacing is smarter for: stiff or jerky handle movement, a tap that no longer fully closes, a water stream that stays uneven despite a clean aerator.

Prevention is cheaper than the cure

A filter stop valve in the water supply catches limescale particles before they reach the cartridge and significantly extends your tap's lifespan — especially relevant in hard-water regions.