A drip is a worn seal, and which seal depends on the tap. Neither answer is a new tap, and both parts cost a few euros.
On a single-lever tap
The ceramic disc cartridge. Its two polished discs no longer meet perfectly, and water passes. Replacing it means matching the diameter — 35 or 40 mm on most — and the shape of its base.
On a two-handle tap
The valve head under the handle, or the washer inside it. Older taps use a rubber washer that hardens; newer two-handle taps use a quarter-turn ceramic head. Both are stocked parts.
If it weeps around the spout rather than dripping from it
That is an O-ring on the body, where a swivelling spout turns. Pennies, and a different job from the cartridge.
The one that is not a seal
A drip that appears only after the water has been running hot is sometimes expansion in the system rather than a fault at the tap. If closing the isolating valve stops it completely and instantly, the tap is where the fault is.
Questions people actually ask
Is a dripping tap worth fixing straight away?
A steady drip wastes a surprising volume over a year, and a worn cartridge also scores its seat if left, which turns a cheap fix into a less cheap one. It is worth doing when noticed.
Can I fix a drip by tightening the tap?
On a modern ceramic tap, no — there is nothing to tighten, and forcing the lever damages the cartridge. On an old washer tap, overtightening is what destroyed the washer in the first place.
Last reviewed 5 September 2026