Fix a leak from the base of a mixer tap

Trace a dripping tap base to worn seals or a loose nut, then isolate the water, replace parts, and test for leaks.

TP-01Work out where the leak is coming fromDry the tap and the area around it with a cloth, then run the tap and watch closely. A leak from where the spout swivels usually means worn O-rings inside the spout collar. A leak from where the tap body sits on the sink or worktop usually means a failed washer or a loose fixing nut underneath. Check both the top of the tap and underneath, in the cupboard below the sink, before you start.

1 each · Cloth or paper towel

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TP-02Turn off the water and drain the tapTurn off the isolation valves under the sink if the tap has them, or shut the stopcock (usually under the kitchen sink) if it does not. Turn the tap fully on to release pressure and drain any water left in the pipe, then leave it open. Have a towel ready to catch the last of the water.

1 each · Old towel

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TP-03Protect the area and get your tools readyPlug the sink so small parts cannot fall down the plughole. Lay a towel in the base of the sink and on the worktop to catch drips and protect the surface. Set out your tools and the new parts so you are not searching for them halfway through.

1 each · Sink plug

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1 each · Old towel

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1 each · Adjustable spanner

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1 each · Basin wrench

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TP-04Remove the tap handle and spoutMost mixer taps have a small cap on the handle hiding a grub screw. Prise the cap off with a flat screwdriver, undo the screw, and lift the handle away. If the leak is from the swivel spout, twist and pull it straight upward off the tap body once any retaining clip or grub screw underneath is released.

1 each · Small flat screwdriver

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1 each · Allen key set

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TP-05Replace the worn O-rings or washerLook for cracked, flattened or perished rubber O-rings on the spout spigot, or a worn washer inside the tap base. Peel off the old O-rings, clean the spigot with a cloth, and roll on new ones of the same size. A light smear of silicone grease helps them seat and slide back in without tearing.

1 each · Tap O-ring repair kit (mixed sizes)

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1 each · Silicone tap grease

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TP-06Check and tighten the fixing nut underneathIf the leak was from the tap base rather than the spout, get underneath the sink and check the large nut that holds the tap in place. Tighten it with a basin wrench, turning clockwise, until snug — do not overtighten, as this can crack a ceramic sink or damage the tap thread. If the sealing washer under the tap base looks flattened or split, replace it before retightening.

1 each · Tap base sealing washer

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1 each · PTFE tape

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TP-07Reassemble the tapPush the spout back onto the tap body and refit any retaining clip or grub screw. Refit the handle, tighten its grub screw, and clip the cap back over it. Check nothing feels loose or wobbly before moving on.

TP-08Turn the water back on and testOpen the isolation valves or stopcock slowly and check underneath the sink first for any drips at the connections. Run the tap for a minute, checking the spout swivel and the base as it runs. Leave it a few minutes and check again, since some leaks only show once the tap has been used a couple of times.

TP-09Tidy upDry the sink and worktop and remove the towels. Dispose of the old O-rings and washer with normal household waste. Keep any leftover new O-rings in a labelled bag in case the tap leaks again on the other side.

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