How to Fix a Leaking Mixer Tap

Fixing a leaking mixer tap can be a straightforward DIY task, however, you might face some complications along the way. If you’re struggling to fix the leak, take a look at the common challenges section at the end of this blog.

Step 1: Turn Off the Water Supply 

Luckily when just fixing a tap, you usually don’t need to turn off the water supply to your home. 

First, look under the sink to find the isolation valves. These are usually small, round or lever-type valves attached to the flexi hoses that supply water to your tap.

To shut off the water, turn these valves until they’re tightly closed. You’ll often need a flathead screwdriver for this. If they’re lever-type valves, turn the lever so it’s perpendicular to the pipe.

After turning off the valves, turn on the tap to ensure there is no water flow. This confirms that the water supply has been successfully cut off. Initially, when you turn off the water supply and start dismantling the tap, there might be residual water in the pipes or the tap itself. Have a bucket and rag ready to catch this water in case this occurs.

Step 2: Remove the Tap Handle/s

The way to remove a tap handle or handles varies from tap to tap, but the main goal for every tap is the same: find and remove the grub screw. 

For many single-handle mixer taps, the grub screw is located beneath a cap/plastic covering on the handle itself. Use a flat-head screwdriver to gently pry this cover off. This is most often the hot/cold indicator on the tap. 

If your single handle tap doesn’t have a hot/cold indicator button, the grub screw might be hidden on the outside of the handle body, usually directly opposite the finger of the handle. 

If you have a dual-handle mixer tap, then the screws might be under the plastic hot/cold caps on either handle, or located somewhere else on the body of the handles. 

Once you’ve found the screw that keeps the handle in place, unscrew it using your Allen key and your tap handle should come straight off. Tip: make sure to plug the sink before taking out the screw so you don’t lose it down the drain! Trust us, we’ve done this before… 

Some models may have a different mechanism for handle removal. If this is the case, find the manufacturer’s guide for further instructions.

Step 3: Dismantle the Tap

With the shifter spanner (adjustable wrench), loosen and remove the tap cover, if necessary. This can be done by hand if the cover is not screwed on too tight. The cover is the domed ring usually located directly beneath the handle of a single-handle mixer tap. Be careful not to damage the surface. This step is not necessary in dual-handle mixer taps. 

Once this is done, you can unscrew the cartridge valve and proceed to the next step. 

If you have a dual-handle mixer tap, you can simply unscrew the spindle or cartridge valve with your shifter once the handles have been removed.  

Step 4: Replace or Clean the O-ring/Washer or Cartridge Valve

Once you’ve removed the cartridge valve or spindles, we recommend examining the parts and replacing any that might be faulty, including the washer, any O-rings, and/or the cartridge valve itself. This ensures you fix the problem and won’t need to do it again for a long while! Make sure to take stock of the parts you’ve removed from your tap and that you have the right replacement for each. 

Step 5: Reassemble the Tap

After replacing all necessary parts, reassemble the tap in reverse order. Ensure everything is tight, but don’t over-tighten as this can cause damage and lead to more leaks further down the track. Hand-tight is usually more than sufficient.

As you reconnect each component, apply thread seal tape to the threaded connections for a secure, leak-free seal. 

Step 6: Test Your Work

Turn the water supply back on and test your tap. Check for smooth operation.

If at any point you feel unsure, remember that DCM Plumbing is here to help. With just a call, our expert team can take over and ensure your mixer tap is fixed with professional care.