How to Fix a Dripping Tap: Step-by-Step Guide for London Homes
Fix a dripping tap yourself in most London homes — covers traditional compression taps, ball valves and ceramic disc cartridges with UK-specific parts guidance.
To fix a dripping tap, turn off the water supply under the sink or at the mains stopcock, remove the tap handle, unscrew the headgear nut, and replace the washer or ceramic cartridge. For traditional UK taps this is a simple washer replacement costing under £2. For modern ceramic disc taps it requires replacing the cartridge (£5-£30).
Key Takeaways
- Victorian and Edwardian London properties (pre-1940s) almost universally have compression taps with replaceable rubber washers — a repair costing under £2 in parts.
- Post-1980s London homes typically have ceramic quarter-turn disc taps requiring cartridge replacement (£5–£30), not washer replacement.
- Always isolate the water supply before starting: use the isolation valve under the sink if present, or the mains stopcock if not.
- In older London properties the stopcock under the sink may be seized — do not force it. See the guide on handling a stuck stopcock before you begin.
- A dripping tap wastes approximately 5,500 litres per year and costs £20–£30 annually on a metered supply, plus significantly more in heated water energy costs.
- Standard UK washer sizes are 1/2 inch (13mm) for most basin and bath taps, 3/4 inch (19mm) for large bath taps and outside taps — always match the old washer.
- Outside taps drip more commonly in London after cold snaps when the washer has cracked due to residual water freezing inside the tap body.
- If a new cartridge has not stopped the drip, check the valve seat inside the tap body for scoring or corrosion — a scored seat requires a seat grinder or tap body replacement.
Why taps drip
A dripping tap is almost always caused by a failed sealing component inside the valve body. In every tap design, water flow is controlled by pressing a flexible or hard seal against a machined seat — when the tap is closed, the seal is compressed against the seat and stops water passing through. When that seal deteriorates, water forces its way past and drips from the spout.
In traditional compression taps — the type with a crosshead or capstan handle that you turn multiple times to close — the seal is a small rubber washer attached to the end of a brass spindle called the jumper. These washers are made of rubber or a nylon-rubber compound and typically last 5–15 years before they harden, crack or deform. London's hard water (around 320–360 mg/L of calcium carbonate) can accelerate washer degradation by depositing limescale on the valve seat, which cuts into the washer over time.
In ceramic disc taps — quarter-turn taps where a single 90-degree rotation opens and closes the valve — the seal is a pair of precision-ground ceramic discs. One disc is fixed, the other rotates. When the discs are aligned, water flows through matching ports; when offset, the ports are blocked and flow stops. Ceramic disc taps are generally more reliable than compression taps but are not immune to failure. The discs can crack under thermal stress, or the O-ring seal around the cartridge body can fail, causing water to leak around the cartridge rather than through the spout.
A third, less common cause in older London properties is a worn valve seat — the brass or gunmetal surface inside the tap body that the washer presses against. If the seat itself is scored, pitted or corroded, even a new washer will not create a watertight seal. Seat damage is more common in very hard water areas and in taps where the washer was allowed to disintegrate and the metal jumper was running directly against the seat.
Types of tap in London homes
Understanding which type of tap you have is the essential first step, because the repair procedure is completely different for each type. In London, the age of the property is the best initial guide.
Victorian and Edwardian properties (pre-1919)
London has more surviving Victorian housing stock than any other UK city. Properties built before around 1919 — which in London includes huge swathes of terraced housing in Islington, Hackney, Lambeth, Southwark, Wandsworth, Hammersmith, Fulham and many other inner boroughs — almost universally retain compression taps with traditional crosshead or capstan handles. These taps are heavy, all-brass or chrome-on-brass construction, often made by British manufacturers such as Pilkington or Smedbo, and can last decades if the washers are replaced periodically.
The key identifying feature of a compression tap is that the handle turns multiple times from fully open to fully closed — typically 3–5 full rotations. If you can spin the handle round and round before hitting resistance, you have a compression tap. The fix is washer replacement, and it costs under £2 in parts.
Inter-war and post-war properties (1919–1980)
Properties built during the inter-war period (1919–1939) and the post-war era through to around 1980 are mixed. Many retain compression taps, particularly in bathrooms that have not been refurbished. Kitchen taps in this era were often replaced during 1970s and 1980s renovation waves and may already be ceramic disc types. If in doubt, the rotation test applies: multiple full turns means compression.
Post-1980s properties and refurbished kitchens and bathrooms
Homes built or substantially refurbished from the 1980s onwards, including modern London new-builds and converted flats with updated kitchens and bathrooms, typically have ceramic quarter-turn disc taps. These open and close with a single 90-degree turn. Most come from European manufacturers (Grohe, Hansgrohe, Bristan are common in London) and use replaceable ceramic cartridges.
Mixer taps — a single fitting with one spout and separate hot and cold handles, or a single lever — can contain either compression or ceramic mechanisms depending on age. In practice, most mixer taps installed since 2000 in London homes use ceramic cartridges.
Tools and parts you need
Gather everything before you isolate the water supply. Working with the water off and having to search for a tool wastes time and increases the chance of a small drip becoming a larger problem.
Tools
- Adjustable spanner or basin wrench (for the headgear nut)
- Flathead and cross-head screwdrivers (for handle screws and isolation valves)
- Grips or pipe grips (for stubborn headgear nuts — protect chrome with a cloth)
- Knife or small flathead screwdriver (to prise off decorative handle covers)
- PTFE tape (for resealing threads on reassembly)
- Silicone grease (for lubricating O-rings and cartridge bodies)
- Bucket or large bowl (to catch water in the tap body when you open it)
Parts — compression taps
- Replacement rubber washer: 1/2 inch (13mm) for standard basin and bath taps; 3/4 inch (19mm) for large bath taps and outside taps. Buy a mixed assortment pack (£3–£5) from any London plumbers merchant or hardware shop if unsure.
- Washer retaining nut or brass jumper (if the existing one is corroded)
- Replacement O-ring for the tap spindle (if the tap is dripping around the spindle rather than from the spout)
Parts — ceramic disc taps
- Replacement ceramic cartridge matched to your tap brand and model. Take the old cartridge to the merchant or photograph the model markings. Common London-market brands: Grohe, Hansgrohe, Bristan, Ideal Standard, Pegler, Armitage Shanks.
- Silicone grease for O-ring lubrication on the new cartridge
Fixing a compression tap (washer replacement)
This repair applies to traditional taps where the handle turns multiple full rotations. In Victorian and Edwardian London properties, this is the standard tap type. The repair is straightforward and should take 15–30 minutes per tap.
Isolate the water supply
Look under the sink for an isolation valve on the hot or cold supply pipe feeding the tap — a small brass valve with a flat-head screw slot. Turn the screw 90 degrees so the slot is perpendicular to the pipe (closed). Then open the dripping tap to release pressure and confirm the water is off. If there is no isolation valve under the sink, you will need to turn off the internal stopcock — typically under the kitchen sink or in a utility cupboard. Turn it clockwise until it stops, then open the tap to drain the line. In older London properties the stopcock under the sink may be seized or corroded — do not force it or you may snap the spindle. See our guide on what to do when a stopcock won't turn in a London flat before attempting to force a stiff valve.
Remove the tap handle
Most tap handles are secured by a screw hidden under a decorative cap or cover on the top of the handle. Prise off the cap with a flathead screwdriver or knife — it will either unclip or unscrew. Remove the retaining screw (usually cross-head) and lift the handle straight up. If it is stuck from limescale build-up, a gentle twist while pulling upward will release it. Do not lever against the tap body.
Unscrew the headgear
With the handle removed, you will see the headgear — a hexagonal brass nut sitting on top of the tap body. This is the main packing nut that holds the spindle assembly in place. Place a cloth over the tap body to protect the chrome finish, grip the headgear nut with your adjustable spanner, and turn anti-clockwise to unscrew. On Victorian-era London taps, this nut may be tight from decades of mineral deposits — apply firm, steady pressure rather than sudden force. Have your bucket underneath as a small amount of water will drip from the tap body when the headgear lifts free.
Remove and inspect the washer
With the headgear out, look at the bottom of the spindle. You will see a rubber washer held in place by a small brass nut (the jumper nut) or pressed into a recess. The washer is the seal — it should be flat, pliable and uncracked. If it is hard, cracked, deformed or missing chunks, this is your drip cause. Unscrew the jumper nut (often a small flat-head operation) and remove the old washer. Also examine the valve seat inside the tap body — shine a torch in and look for the brass ring the washer presses against. It should be smooth and even. If it is scored or has a groove worn into it, a new washer alone will not stop the drip; the seat needs grinding or replacement.
Fit the new washer
Select the correct washer size: 1/2 inch (13mm) for a standard basin or bath tap, 3/4 inch (19mm) for a larger bath tap or outside tap. Press the new washer into the recess or onto the jumper and secure the jumper nut finger-tight. Do not overtighten — the washer needs to compress evenly, not be distorted by excessive clamping force. If the jumper nut is corroded, replace the entire jumper assembly, which is available cheaply at any plumbing merchant.
Reassemble and test
Inspect the O-ring on the spindle — the rubber ring that seals the spindle where it passes through the headgear body. If it is cracked or deformed, replace it now while everything is apart; it is the cause of any dripping or weeping from around the spindle rather than from the spout. Apply a small amount of silicone grease to the O-ring. Reinsert the headgear into the tap body and tighten the headgear nut clockwise — firm but not over-torqued. Refit the handle and handle screw. Reopen the isolation valve or stopcock, then slowly open the tap. Close it fully and watch for drips. If the drip has stopped, the repair is complete.
Fixing a ceramic disc tap (cartridge replacement)
Ceramic disc taps are identified by their quarter-turn action — a single 90-degree rotation from fully open to fully closed. This repair replaces the entire cartridge assembly inside the tap body. It takes 20–40 minutes and the main challenge is sourcing the correct replacement cartridge.
Isolate the water supply
As with compression taps, find the isolation valve under the sink on the relevant supply pipe (hot or cold depending on which tap is dripping) and turn it 90 degrees to close. Open the dripping tap to release remaining pressure and confirm the water is isolated. For a single-lever mixer tap, isolate both hot and cold supplies before opening the body. If there is no isolation valve and the stopcock is seized, see the note in the compression tap section and our guide on stuck stopcocks in London flats.
Remove the handle
Quarter-turn tap handles typically have a retaining screw under a decorative cap at the top or rear of the handle. Remove the cap and unscrew the retaining screw. The handle should then lift straight off. On some designs — particularly Grohe and Hansgrohe taps common in London refurbishments — the handle may have an additional locking ring below the handle body that needs to be unscrewed by hand before the handle lifts free.
Remove the retaining nut or shroud
Below the handle, there may be a decorative shroud or escutcheon that unscrews by hand or with a spanner. Under that is the retaining nut that holds the cartridge in the tap body. Unscrew the retaining nut anti-clockwise using an adjustable spanner. The cartridge will then lift straight out of the tap body — note its orientation before removing it, as cartridges must be reinstalled in the same rotational position.
Identify and source the replacement cartridge
Take the old cartridge to the plumbing merchant or photograph the markings on its body. Key identifiers are the cartridge diameter (typically 35mm or 40mm for mixer taps), the brand marking, and any part number stamped on the body. Common cartridge brands in London homes include Grohe 46374, Hansgrohe 94041, Bristan cartridges, and Ideal Standard A951766. A universal cartridge rarely performs as well as the OEM part — spend the extra few pounds on the correct cartridge for your tap brand. Prices range from £5 for basic replacement washered cartridges to £30 for branded ceramic cartridges for premium tap brands.
Inspect the tap body and fit the new cartridge
Before fitting the new cartridge, inspect the inside of the tap body where the cartridge sits. Wipe away any debris or limescale deposits with a damp cloth. Apply a thin film of silicone grease to the O-rings on the body of the new cartridge — this prevents the O-rings from tearing on insertion and ensures a good seal. Insert the new cartridge in the same rotational orientation as the old one (most cartridges have alignment slots or lugs that only allow them to fit one way). Press down firmly to seat it fully.
Reassemble and test
Refit the retaining nut and tighten it clockwise — firm but not over-torqued, as ceramic cartridges can crack if the retaining nut is over-tightened. Refit any decorative shroud or escutcheon, then refit the handle and retaining screw. Reopen the isolation valve, then slowly operate the tap through its full range of motion a few times. Close it fully and observe for 60 seconds. If there is no drip from the spout or from around the body of the tap, the repair is complete. If the tap still drips, see the FAQ below on troubleshooting a cartridge replacement that has not resolved the drip.
Dripping outside tap
Outside taps in London are a common source of drips, particularly in the weeks following a cold snap. When temperatures drop below freezing — which happens several times per winter in London — residual water in the outside tap body can freeze, expanding and cracking the internal washer or, in severe cases, the tap body itself.
Most London outside taps are compression-type bib taps — a simple crosshead or lever handle with a horizontal spout, mounted on an outside wall. The washer size is typically 3/4 inch (19mm). The repair procedure is the same as for an indoor compression tap, with two important differences.
First, outside tap supply pipes typically have a separate isolation valve inside the house — often in the kitchen cupboard or utility room on the pipe leading out through the wall. This should be your isolation point rather than the mains stopcock, as it allows you to keep the rest of the house water running while you work.
Second, outside tap bodies are often more corroded than indoor taps due to weather exposure. The headgear nut may be seized. Apply penetrating oil (WD-40 or similar) to the nut and leave it for 15 minutes before attempting to turn it. If it will not move with firm spanner pressure, do not force it — call a same-day plumber rather than risk snapping the nut or tap body.
If the outside tap body itself has a crack — visible as water emerging from the tap body when in use, not just from the spout — the tap body needs replacing. This is a straightforward job for a plumber: an outside bib tap costs £15–£30 in parts and the labour is typically under an hour, but requires soldering or push-fit work on the internal supply pipe.
Cost of ignoring a dripping tap
A dripping tap is easy to put off — it seems minor. The financial and practical case for fixing it promptly is stronger than most London homeowners realise.
| Drip rate | Litres wasted per year | Approximate annual cost (metered supply) | Extra cost if hot tap |
|---|---|---|---|
| Slow drip (1 per second) | ~5,500 litres | ~£20–£30 | Add £40–£80 in heating costs |
| Fast drip (2–3 per second) | ~15,000 litres | ~£55–£80 | Add £100–£200 in heating costs |
| Trickling tap | ~30,000+ litres | ~£110–£160 | Add £200–£400 in heating costs |
London water is metered for most modern properties and a growing proportion of older ones. Thames Water charges approximately £1.95 per cubic metre (1,000 litres) for water plus a similar amount for wastewater removal — so the real cost per litre wasted is roughly £0.004, or around £22 per year for a standard slow drip at 1 drop per second. That figure roughly doubles if the drip is hot water, given gas and electricity costs for heating it.
Beyond the water and energy bill, there is the matter of what the dripping tap represents. A worn washer or failing cartridge is an indication that the tap valve has reached the end of its service life for that component. Compression tap washers that are left unreplaced eventually degrade to the point where the metal jumper seats against the brass valve seat — at that point the seat itself becomes scored and a washer replacement alone will no longer seal the tap. What could have been a £2 washer repair becomes a seat regrind or a complete bathroom tap replacement costing £80–£200.
Ceramic cartridge taps that are left dripping face a different failure progression — the cracked ceramic disc or failed O-ring allows water past the cartridge body, which can lead to water tracking inside the tap body, dripping under the sink without being immediately visible, and eventually causing mould and rot in the under-sink cabinet.
For a 24/7 plumber in London who can diagnose and repair dripping taps across all 33 boroughs, our £60 call-out fee is waived on jobs that run over two hours. A dripping tap repair is typically a short job within a single call-out, and with the call-out fee included, professional repair costs £80–£150 — less than three months of wasted water and heating from a moderate drip.
Dripping tap you can't fix yourself?
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📞 Call 020 7870 3200Frequently asked questions
Why does my tap drip after I turn it off?
A tap that drips immediately after being turned off has a worn washer or ceramic cartridge. The sealing surface that closes off flow is no longer making a complete seal. In traditional compression taps this is always a rubber washer failure. In modern quarter-turn ceramic disc taps it is usually a cracked or worn ceramic disc or a failed O-ring seal on the cartridge body.
Is a dripping tap worth fixing myself in London?
Yes — a slowly dripping tap wastes approximately 5,500 litres per year and costs around £20–30 annually on a metered supply. More importantly, a dripping hot tap wastes heated water, costing significantly more on your energy bill. The repair costs £0–30 in parts and takes under an hour for most people. A plumber call-out to fix a dripping tap typically costs £80–150 in London.
What size tap washer do London taps use?
The most common washer sizes in UK taps are 1/2 inch (13mm) for standard basin and bath taps, and 3/4 inch (19mm) for larger bath taps and outdoor taps. Always bring the old washer to the plumbers merchant to match the size — or buy a mixed pack (available for under £5 at most London plumbers merchants and hardware stores).
My ceramic disc tap is still dripping after I replaced the cartridge — what now?
If a new cartridge has not stopped the drip, check: (1) the cartridge was the correct model for your tap brand; (2) the valve seat inside the tap body is scored or corroded; (3) the O-ring on the cartridge body was correctly greased with silicone grease before insertion.
Can a dripping tap cause water damage?
A dripping tap itself rarely causes structural water damage because it drips into a drain. However, a dripping tap under a sink that goes unnoticed can drip onto the cabinet floor causing mould and wood rot over months. More seriously, a dripping tap is often an early sign of a failing valve that may ultimately fail completely.