How to Fix a Dripping Tap: Step-by-Step Guide (2026)

Q: How much water does a dripping tap waste?

A tap dripping at one drop per second wastes approximately 15,000 litres of water per year. A slower drip of around one drop every 3 seconds still wastes approximately 5,500 litres per year. At London water rates (Thames Water charges approximately £1.60 per cubic metre), this costs £9–£24 per year in water alone — plus hot water heating costs if it's the hot tap.

Q: How do I know if I need to replace a washer or a cartridge?

Traditional pillar taps (separate hot and cold taps that turn multiple rotations) use rubber washers. Modern mixer taps with a quarter-turn mechanism (turn 90 degrees from off to full flow) use ceramic disc cartridges. Lever-handle mixer taps may use either, depending on the make.

Q: Why does my tap drip only at night?

Mains water pressure in London increases at night when demand drops — typically rising to 4–6 bar compared to 2–3 bar during daytime peak hours. Higher pressure forces more water past a worn washer or cartridge, making a drip that was barely noticeable by day sound constant at night. The fix is the same — washer or cartridge replacement.

A dripping tap wastes 5,500 litres of water per year and costs around £30–£60 annually on UK water bills. Learn how to replace a tap washer or cartridge yourself — and when to call a plumber.

A dripping tap is one of those household problems easy to dismiss — until you calculate what it costs. A slow drip of one drop every three seconds wastes approximately 5,500 litres of water per year. At Thames Water's metered rates (approximately £1.60 per cubic metre in 2025/26), that's around £9 per year in water — and significantly more if it's the hot tap, where you're also paying to heat every drop.

More importantly, fixing a dripping tap is one of the most achievable DIY plumbing jobs in a London home. A replacement washer costs £0.50–£2, the tools are basic, and the job takes 30–45 minutes. Over 14 years working across London properties, we've shown many homeowners how to do this themselves — and we always encourage people to try.

The Real Cost of a Dripping Tap

Drip Rate	Litres Wasted / Year	Water Bill Cost (metered)	Extra if Hot Tap
1 drop every 10 seconds	~1,600 litres	~£2.50/year	+£3–£5/year
1 drop every 3 seconds	~5,500 litres	~£9/year	+£10–£18/year
1 drop per second	~15,000 litres	~£24/year	+£28–£50/year
Continuous slow stream	~60,000+ litres	~£96+/year	+£100+/year

These figures assume a metered supply — the majority of London properties now have water meters. Thames Water's move toward universal metering means this cost increasingly applies to every London household.

Types of Taps: Which Do You Have?

Traditional Pillar Taps (Separate Hot and Cold)

These turn multiple rotations from off to fully open. They use a rubber washer that compresses against a metal seat to stop water flow. Very common in London's older housing stock — Victorian and Edwardian properties frequently have these in original bathrooms and kitchens. The washer wears with use and needs periodic replacement.

Ceramic Disc Mixer Taps (Quarter-Turn)

These turn just 90 degrees from off to fully open. They use a ceramic disc cartridge — two discs that rotate to align or block water holes. Common in modern fittings installed in the last 20 years. When they drip, you replace the ceramic cartridge rather than a washer.

Lever Mixer Taps

A single lever controls both temperature and flow. May use either a washer or cartridge depending on the brand. Check manufacturer documentation before disassembling.

What You'll Need

Adjustable spanner or dedicated tap spanner
Flat-head and cross-head screwdrivers
Replacement washer matching the existing size (usually 1/2 inch or 3/4 inch) — £0.50–£2 from Screwfix, B&Q, or Wickes
PTFE tape for resealing threads if any appear worn
Old towel or bowl to catch residual water

💡 Washer size tip: If unsure which size to buy before opening the tap, purchase an assorted tap washer kit (£3–£5 at Screwfix) containing several sizes — this covers virtually every UK tap size. Alternatively, open the tap first, take the old washer to the DIY store, and match it directly.

How to Fix a Pillar Tap (Washer Replacement)

Turn off the water supply

Close the isolation valve under the sink (slotted screw — turn clockwise until the slot is at 90 degrees to the pipe). If there is no isolation valve, turn off the main stopcock. Open the tap to release pressure and drain the pipe.

Remove the tap handle

Prise off the hot/cold indicator cap on top of the handle. Unscrew the retaining screw beneath it — usually cross-head. Lift the handle straight off the spindle.

Remove the tap shroud

Some taps have a decorative shroud beneath the handle that unscrews by hand. Remove this to expose the headgear nut below.

Unscrew the headgear

Use an adjustable spanner to unscrew the headgear nut (large hexagonal nut) anti-clockwise. This may require significant force on older London taps. Protect the tap body from scratching with a cloth around the spanner jaw. Lift out the entire headgear assembly.

Replace the washer

At the bottom of the headgear spindle, unscrew the small brass nut holding the old rubber washer. Remove the old washer — note its size — and fit the new one of the same diameter. Tighten the nut firmly but not so hard it deforms the new washer.

Inspect the tap seat

Look down into the tap body where the headgear came from. The metal surface the washer compresses against (the seat) should be smooth and flat. If it looks pitted or rough, see the tap seat section below before reassembling.

Reassemble and test

Screw the headgear back in clockwise (firmly but not overtight — you may need access again). Replace the shroud, refit the handle, and replace the indicator cap and screw. Turn the water supply back on slowly. Test the tap.

How to Fix a Ceramic Disc Mixer Tap (Cartridge Replacement)

For quarter-turn mixer taps, the process is similar to the above up to removing the headgear. Instead of a rubber washer, you will find a ceramic cartridge assembly.

Remove the handle and unscrew the retaining nut as above
Note the exact orientation of the ceramic cartridge before removing — photograph it
Pull the ceramic cartridge straight out
Take the cartridge to a plumbing merchant or order a replacement online — cartridges are brand and model specific (Grohe, Hansgrohe, Bristan, Ideal Standard are common in London homes)
Insert the new cartridge in exactly the same orientation
Reassemble and test

✅ Cartridge matching: Many common Grohe, Hansgrohe, Bristan, and Ideal Standard cartridges are stocked by Plumb Center and similar London plumbing merchants. Bring the old cartridge with you. For less common brands, the manufacturer's website usually stocks spares directly.

When the Tap Seat Is Damaged

If you replace the washer but the tap still drips, the metal tap seat may be damaged — pitted, grooved, or corroded. A new rubber washer cannot form a proper seal against a rough seat.

Reseating tool (DIY): A tap reseating tool (£15–£30 from Screwfix) grinds the seat back to a smooth surface. Achievable as a DIY job with patience.
Washer and seating set: Some kits include a replacement seat that screws into the tap body — simpler to fit than grinding.
Tap replacement: If the seat is beyond repair and the tap is old, replacement is often the most practical option. A plumber can supply and fit a replacement for £150–£300 in London.

London Hard Water and Tap Wear

London's hard water (approximately 300mg/L) accelerates tap wear in two ways: limescale deposits build up on the tap seat, creating irregular surfaces that prevent washers from sealing correctly; and mineral deposits accumulate inside the headgear, making the tap stiffer to turn. This forces users to apply more torque to close the tap, compressing the washer more aggressively and wearing it faster.

London taps typically need washer replacement every 3–5 years in hard water areas, compared to every 10+ years in soft water regions like South Wales or Scotland. Adding a water softener (£500–£1,200 installed) extends the life of all tap components significantly — and also protects the boiler and other appliances.

When to Call a Plumber

Call a professional if:

The tap seat is visibly damaged and you don't want to use a reseating tool
The tap is an unusual or premium brand with non-standard parts
The isolation valve under the sink also leaks when you try to close it
There is no isolation valve and you cannot locate the main stopcock
The tap body is cracked or corroded — requires full replacement
The leak is from the base of the tap or where the tap meets the basin

Our emergency plumber London service handles tap repairs and replacements same day across all 32 London boroughs. For more complex leaks involving supply pipes, our leak detection London team can locate any hidden source.

Dripping Tap in London? We'll Fix It Today.

Our London plumbers fix dripping taps, replace washers and cartridges, and supply and fit new taps same day. Fixed price before we start, across all 32 boroughs.

Call 07456 975436

Frequently Asked Questions

How much water does a dripping tap waste per year?

A tap dripping at one drop every three seconds wastes approximately 5,500 litres of water per year — costing around £9 at Thames Water's metered rates. A faster drip of one drop per second wastes roughly 15,000 litres (£24 in water alone). If it's the hot tap, add heating costs on top.

How do I know if I need to replace a washer or a cartridge?

Traditional taps that turn multiple rotations use rubber washers. Modern quarter-turn taps (turn 90 degrees from off to full flow) use ceramic disc cartridges. The repair process is slightly different for each type, but both are achievable as DIY jobs with basic tools.

Can I fix a dripping tap myself?

Yes — if you have basic DIY skills and can turn off the water supply. A replacement washer costs £0.50–£2, the tools are simple (spanner and screwdriver), and the process takes 30–45 minutes. We'd recommend calling a plumber if the tap seat is damaged, the isolation valve is broken, or the tap body is cracked.

How much does a plumber charge to fix a dripping tap in London?

A plumber in London typically charges £80–£130 to fix a dripping tap including parts. If tap replacement is needed, budget £150–£300 for supply and fit depending on the tap specification. Emergency out-of-hours call-outs add £50–£100.

Why does my tap drip only at night?

Water pressure in London increases at night when demand drops — typically rising to 4–6 bar compared to 2–3 bar during peak daytime hours. Higher pressure forces more water past a worn washer or cartridge, making a drip barely noticeable by day sound constant at night. The fix is the same — washer or cartridge replacement — and it's completely expected behaviour with a worn tap.