Leaking Tap Repair Guide for Eltham Homeowners

Published July 2026 | Leaking Tap Repair

This guide walks you through diagnosing and fixing the most common types of leaking tap in UK homes, from dripping kitchen taps to weeping bathroom mixer taps. It's written for Eltham homeowners who want to tackle the repair themselves before deciding whether to call in a plumber.

Before You Start - Safety First

A leaking tap might seem like a minor nuisance, but left unattended it can waste thousands of litres of water per year and push up your water bill significantly. Before you pick up a spanner, there are a few things you need to do to make the job safe and avoid turning a drip into a flood.

Turn off the water supply. Most taps in UK homes are fed by an isolation valve on the supply pipe beneath the sink or basin - it's usually a slotted screw that you turn 90 degrees with a flathead screwdriver. If you cannot find an isolation valve, you'll need to turn off the main stopcock, which is typically located under the kitchen sink or where the water main enters the property. Once you've isolated the supply, open the tap fully to release any residual pressure and drain the water sitting in the pipe.

Put the plug in the basin or sink before you start. Tiny components - washers, O-rings, small screws - have a habit of vanishing down the drain at the worst possible moment. Keep a towel handy too, as some residual water will still sit in the tap body when you dismantle it.

What You Will Need

The tools and materials you need depend on what type of tap you have. There are two main types you'll encounter in Eltham homes: traditional pillar taps (the kind with separate hot and cold handles) and cartridge mixer taps (the single-lever or twin-handled type found in modern kitchens and bathrooms).

Tools:

• Adjustable spanner or basin wrench
• Flathead and crosshead screwdrivers
• Slip-joint pliers (with cloth or tape to protect chrome finishes)
• Allen key set (for taps with grub screws)
• Cartridge puller (for stubborn cartridges - optional but useful)

Materials:

• Replacement washers (typically 12mm, 15mm, or 19mm - take the old one to a plumber's merchant to match it)
• O-ring set (a mixed pack covering common sizes is a sensible investment)
• Replacement cartridge (if you have a mixer tap - match the brand, which may be Bristan, Grohe, Hansgrohe, or a supermarket own-brand)
• PTFE tape
• Plumber's grease (silicone-based)

Time estimate: A washer or O-ring replacement on a pillar tap typically takes 30 to 60 minutes if you have the right parts to hand. A cartridge replacement on a mixer tap can take a similar amount of time, though tracking down the correct cartridge beforehand may add to that. Allow more time if you're working on an older tap that hasn't been touched in years - seized components slow everything down considerably.

Step-by-Step Instructions

Step 1: Identify Where the Leak Is Coming From

Before dismantling anything, watch the tap carefully. Is it dripping from the spout? That usually points to a worn washer or cartridge. Is it weeping around the base of the handle or where the tap meets the basin? That's more likely to be a failing O-ring or a loose packing nut. Is water coming from beneath the sink? Check the supply connections first - sometimes a leak isn't in the tap body at all but in a compression fitting or flexi hose. Getting this right at the start saves a lot of unnecessary work.

Step 2: Remove the Tap Handle

Most tap handles are held in place by a decorative cap that conceals a screw underneath. Prise the cap off gently with a flathead screwdriver - it's usually friction-fit or screwed on loosely. Once you remove the screw (crosshead or Allen key), the handle should lift straight off. If it's stuck, don't force it. A gentle wiggle while pulling upwards usually does the trick. On older taps, especially in Eltham period properties where the plumbing hasn't been updated for decades, handles can be corroded on. Penetrating oil applied around the base and left for 15 minutes usually frees them.

Step 3: Remove the Headgear or Cartridge

For a traditional pillar tap, you'll see the headgear - a brass nut that holds the valve mechanism in place. Use an adjustable spanner to unscrew it anti-clockwise. Once it's off, you can pull out the entire valve assembly and access the washer at the bottom, which is held in place by a small nut. For a mixer tap, once the handle is removed you'll typically see a retaining clip or nut securing the cartridge. Remove this and pull the cartridge straight out. Some cartridges come out easily; others need a cartridge puller. Note which way the cartridge is oriented before removing it - they're direction-specific.

Step 4: Replace the Washer or Cartridge

On a pillar tap, unscrew the small nut at the base of the valve and remove the old washer. Compare it with your replacement to make sure they match in diameter and thickness - this matters more than people realise. Fit the new washer and reassemble the nut. If the brass seating inside the tap body looks pitted or scored, the tap may be beyond a simple washer replacement (more on that below). On a mixer tap, fit the new cartridge in the same orientation as the old one, making sure it seats fully before replacing the retaining clip or nut.

Step 5: Replace Any O-Rings

While you've got the tap apart, check the O-rings on the headgear or cartridge body. These rubber rings seal the joint between moving parts and the tap body - when they deteriorate, you get weeping around the handle rather than from the spout. Roll each O-ring off carefully and compare it with your spares. Apply a thin coat of silicone grease to the new O-ring before fitting it - this helps it seat properly and extends its working life considerably.

Step 6: Reassemble the Tap

Put everything back together in reverse order. Tighten the headgear nut firmly but don't overtighten it - you're dealing with brass threads and they strip more easily than steel. Refit the handle and push or screw the decorative cap back in place. If you used PTFE tape on any threads, make sure the tape is wound clockwise when looking at the thread end, so it doesn't unwind as you tighten up.

Step 7: Turn the Water Back On and Test

Open the isolation valve slowly and let the system repressurise. Turn the tap on and off a few times and watch carefully for drips - at the spout, around the handle, and at the base. If everything looks dry, run the tap normally for a minute and check again. Leave a piece of dry tissue paper under the tap and under the sink overnight - it'll show up even the smallest drip you might miss during a quick visual check.

What to Do If This Does Not Fix It

If the tap is still dripping after a washer replacement, the most likely cause is a damaged valve seat inside the tap body. The seat is the brass surface that the washer presses against to form a seal, and over time it can become pitted or grooved - meaning even a new washer can't form a proper seal against it. You can buy a tap reseating tool from a plumber's merchant for around 15 to 25 pounds, and this can restore a damaged seat without replacing the whole tap.

If the cartridge on a mixer tap is still leaking after replacement, double-check that it's the correct cartridge for your tap brand and model. Our engineers at Voltrade have used the GoFIX diagnostic tool to trace persistent mixer tap leaks back to incorrect cartridge sizing - a 35mm cartridge in a 40mm housing will never seal properly no matter how many times you replace it. The brand matters too: a Bristan cartridge won't fit a Grohe tap body.

For leaks around supply connections - the flexi hoses or compression fittings under the sink - check that all fittings are tight and that the olive (the small brass ring inside a compression fitting) hasn't been damaged. If a compression fitting continues to weep, it's often more practical to replace the whole flexi hose than to try to reseat a damaged olive.

When to Stop and Call a Professional

Some tap repairs are well within a confident DIYer's capability. Others are better left to a qualified plumber. In Greater London, particularly in areas like Eltham where a mix of Victorian terraced houses and post-war properties means you encounter every era of plumbing, knowing when to stop is genuinely important.

Call a plumber if:

• The tap body itself is cracked or corroded - no repair will hold long-term and the tap needs replacing
• The isolation valve won't close fully, meaning you cannot isolate the supply safely
• The main stopcock is seized or leaking - this needs professional attention before any tap work can be done safely
• Water is coming through the ceiling from an upstairs bathroom - this could indicate a burst pipe rather than a tap problem
• The leak is from a hot water tap and you have a combination boiler or unvented cylinder - the system may be overpressurising, which needs a qualified plumber to diagnose correctly
• You've replaced the washer and cartridge and the tap is still dripping despite a sound valve seat

A professional tap repair or replacement in Greater London typically costs between 80 and 180 pounds for a basic job, depending on parts and access. Replacing a tap entirely - where the existing one is beyond economical repair - commonly runs to 150 to 300 pounds including materials. If you're in Eltham and calling out a local plumber, always check they're registered with WaterSafe, which is the UK's authoritative register for approved plumbing businesses.

Questions About This Process

How do I know if I have a washer tap or a cartridge tap?

Washer taps have a round handle that you turn multiple times to open or close the flow - typically two full turns or more. Cartridge taps, including most modern mixer taps, use a quarter-turn lever or a handle that moves through a shorter arc. If your tap has separate hot and cold fittings with cross-head or capstan handles, it's almost certainly a washer type. If it has a single lever or turns with a short twist, it's cartridge-based. When in doubt, disassemble carefully and you'll see immediately which type of internal mechanism you're dealing with.

Can a dripping tap cause serious damage to my home?

A slow drip can waste anywhere from 5,000 to 20,000 litres of water per year depending on the severity, which has a real impact on metered water bills across Greater London. In Eltham and the wider Greater London area, water hardness is high, so mineral deposits from even a small drip accumulate faster than in softer-water regions - staining sinks and building limescale quickly. If the leak is at a connection under the sink rather than from the spout, there's also a risk of water damage to cabinetry and flooring over time.

What is the difference between a washer and an O-ring, and how do I know which one to replace?

A washer is a flat disc - usually rubber or synthetic rubber - that presses against the tap seat to stop water flowing through the spout when the tap is closed. An O-ring is a circular rubber ring that seals a rotating or sliding joint elsewhere in the tap, typically around the spindle or cartridge body. If your tap drips from the spout when closed, the washer or cartridge is the likely culprit. If water weeps around the handle during use, an O-ring is more probable. When you've got the tap apart, it costs little to replace both at once.