Two types of tap, two different faults
Traditional compression taps, the kind with a separate handle that you turn through multiple rotations to fully open or close, seal using a rubber or fibre washer pressed onto a metal seat. Over time the washer perishes and hardens, or the seat itself becomes scored and pitted, usually from grit or scale in the water, and the tap can no longer form a tight seal even when fully closed. This shows up as a steady drip from the spout.
Modern quarter-turn taps, including most mixer taps and monobloc single-lever designs, use a ceramic disc cartridge instead of a washer. Two polished ceramic discs slide across each other to open and close the flow. These rarely wear out from simple use, but limescale and grit can score the discs over years, or a cartridge can fail outright, again giving a drip from the spout that gets worse over time.
Dripping from the spout vs weeping at the base
Where the water appears tells you a lot. A drip from the end of the spout, whether constant or only after the tap has been used, points to the washer, seat or cartridge inside the tap body itself not sealing fully. Water appearing around the base of the tap, or around the handle, on the other hand usually means a worn O-ring rather than a washer or cartridge fault: O-rings seal the moving spout or handle spindle against the tap body, and like washers they harden and perish with age.
On monobloc mixer taps, which combine hot and cold into a single spout fed by two flexible tails underneath, a base leak can also mean the tails themselves or their connections have loosened, which is worth checking under the sink or basin before assuming the tap body itself is at fault.
| Where the drip appears | Tap type | Likely cause |
|---|---|---|
| Steady drip from spout | Traditional handle tap | Worn washer or scored valve seat |
| Drip from spout, worse over months | Quarter-turn/mixer tap | Worn or scored ceramic disc cartridge |
| Weeping around the handle or spout base | Either type | Perished O-ring |
| Leak under the basin/sink at the tails | Monobloc mixer | Loose or worn tail connection |
What you can safely do yourself
Fixing a dripping tap yourself is one of the more accessible DIY plumbing jobs, provided you can isolate the water supply, either at dedicated isolation valves under the basin or bath, or at the stopcock if there are none. Turn the tap on afterwards to release pressure before starting work.
For a compression tap, the handle usually lifts or unscrews to reveal a headgear nut, which undoes to expose the washer on the end of the spindle, a cheap and simple swap. For a quarter-turn tap, the handle cap and grub screw hide a retaining nut around the cartridge, which lifts straight out once undone, ready to be replaced with a matching new one.
The main thing to get right on a cartridge tap is buying the correct replacement, since cartridges vary between manufacturers and even between models from the same maker. Taking the old cartridge to a plumbers' merchant, or checking the tap brand and model, saves a wasted trip. If the tap is out of production or an unusual design, sourcing an exact match can be difficult.
When a tap is not worth repairing
Basic washers and standard cartridges are inexpensive, generally a few pounds to perhaps £15-£25 for a branded cartridge, so repair is nearly always worth trying first on a tap you like and that is otherwise in good condition. However, if the tap is old, chrome plating is worn or pitted, the spout itself is loose or corroded, or you cannot find a matching cartridge, replacing the whole tap is often the more sensible option, particularly since fitting a new washer or cartridge into a badly corroded body sometimes only buys a short reprieve before something else fails.
It is also worth considering replacement if you are already changing other fittings in the bathroom, since matching a new tap to a new basin or bath is often neater than reusing an older, mismatched design.
Hard water in Berkshire and the Thames Valley
Reading and much of the surrounding Thames Valley area sits on a hard water supply, which means the water carries more dissolved limescale than in softer-water parts of the country. This accelerates wear inside taps: scale builds up on washers and seats, and can scratch or coat ceramic discs, making drips and stiff operation more common here than in a soft-water area. Wiping taps dry after use and an occasional descale of the spout aerator with a limescale remover helps, but it does not stop internal wear altogether, so taps in this area may need washers or cartridges replacing somewhat more often than the manufacturer's typical estimate.
Your questions answered
Why has my tap started dripping only recently?
A sudden new drip after years of trouble-free use is usually a washer or O-ring that has finally perished, or grit from recent works elsewhere in the plumbing system (such as a new fitting or a burst nearby) getting lodged against the seat or cartridge. Isolating the tap and checking inside will usually confirm which.
Can I fix a dripping tap without turning off the water to the whole house?
Yes, if the tap has its own isolation valves, usually small chrome or plastic valves under the basin or bath that you turn with a flat screwdriver or by hand. If there are no isolation valves fitted, you will need to use the main stopcock instead.
How do I know if I need a washer or a cartridge?
It depends on the tap design. Traditional taps with a handle you turn through several full rotations use a washer. Taps that open and close with a quarter turn, including most modern mixer and monobloc taps, use a ceramic disc cartridge instead.
Why does hard water make taps drip more often in this area?
Reading and the wider Thames Valley have a hard water supply, meaning it carries more dissolved limescale than softer water elsewhere. This scale builds up on washers and seats and can score ceramic discs, so taps here tend to develop drips somewhat sooner than the same tap would in a soft water area.
Is it worth repairing an old tap or should I replace it?
If the tap body, spout and finish are all in good condition, a washer or cartridge repair is usually the cheaper and quicker option. If the plating is worn, the spout is loose, or you cannot get a matching cartridge, replacing the whole tap tends to give a longer-lasting result.