A dripping kitchen sink mixer tap is one of the most common household nuisances, wasting water and creating an irritating constant drip. While it might seem like a job for a professional, the vast majority of leaks are caused by worn washers or O-rings that are easy to replace with basic tools. This guide will walk you through a systematic approach to diagnosing the exact source of the leak and fixing it safely, saving you money and preventing further damage to your plumbing.
Safety First: Preparing Your Work Area
Before you touch any part of the tap, turning off the water supply is non-negotiable. Locate the isolation valves under the sink; they are usually small valves connected to the hot and cold water pipes. Turn them clockwise until they stop, shutting off the flow to the tap. If your valves are stuck or you have an older property without isolation valves, you will need to turn off the main water supply to the house. After shutting the water off, turn on the kitchen tap itself to drain any remaining water from the pipes and ensure the system is empty.
Gather Your Tools and Parts
Having the right tools ready prevents frustrating interruptions mid-repair. You will typically need an adjustable wrench, a flat-head screwdriver, a Philips head screwdriver, and a packet of cloths to catch any residual water. The most critical step is identifying the correct replacement parts. Take a small broken component—such as a worn rubber washer or a loose screw—from the tap to a local hardware store to match the exact size and type. Modern mixer taps often use specific sized washers, so generic supplies might not fit.
Disassembling the Tap Handle
Most leaks originate from the spout or the base of the tap where the handle sits, and fixing this requires accessing the internal cartridge or valve mechanism. Start by removing the handle screw, which is often hidden under a decorative cap on the top of the handle. Use a flat-head screwdriver to gently pry off this cap, revealing the screw underneath. Once the screw is removed, carefully lift the handle straight off the stem of the tap.
You will likely see a retaining nut or a collar securing the cartridge in place. Use your adjustable wrench to loosen this nut carefully, supporting the cartridge underneath so it does not fall into the wall cavity. Once the retaining nut is off, you can pull the cartridge out slowly. Inspect the O-rings located on the shaft of the cartridge; these are the usual culprits for leaks occurring when the handle is turned on or off.
| Component | Purpose | Common Failure Signs |
|---|---|---|
| Rubber Washer | Creates a seal against the valve seat to stop water flow. | Water dripping from the spout when the tap is off. |
| O-Ring | Prevents water from leaking around the handle stem or cartridge. | Moisture or dripping around the base of the tap handle. |
| Cartridge | Controls the mixture of hot and cold water. | Leaks from the handle or difficulty in turning the handle. |
Identifying the Source of the Leak
Not all dripping comes from the same place, and pinpointing the exact leak point determines the repair method. If the water is pooling around the base of the tap where it connects to the sink deck, the leak is likely coming from the cartridge or the mounting seals. If the drip is coming from the handle or the spout while the tap is closed, the issue is almost certainly with the seat washer or the O-ring on the cartridge stem.
For leaks that occur when the water is running, the issue is usually with the internal ceramic disks or the washer that seals the inlet. If you notice limescale build-up around the spout, this can prevent the washer from seating correctly, allowing water to seep through. Cleaning the valve seat with a specialized descaling solution or a vinegar soak can sometimes solve the issue without replacing parts.
Replacing the Washers and Reassembly
Once you have identified the faulty component, replacing it is straightforward. If you are replacing a rubber washer, use your old washer to cut an exact replica from a new one, ensuring a tight seal. Coat the new washer and the valve seat with a thin layer of plumber’s grease or silicone grease to ensure a watertight fit and protect the rubber from future wear. Reinsert the cartridge, tighten the retaining nut securely with your wrench, and reattach the handle, making sure the screw is snug but not overly tight to avoid cracking the ceramic internals.
Testing the Repair
With the tap fully reassembled, slowly turn the isolation valves counterclockwise to restore the water supply. Do not rush this step; turning the valves too fast can create a water hammer effect that damages the seals. Once the water is flowing, test the tap by turning the handle on and off and checking for any drips. Inspect the areas you repaired closely for the first few minutes to confirm the leak has stopped.
If the dripping persists after the repair, the issue may be more complex, such as a crack in the tap body or a failure in the internal cartridge that requires full replacement. However, for the majority of kitchen sinks, replacing the washers resolves the issue completely, restoring full functionality and eliminating that constant, wasteful drip.
