Replacing a dripping kitchen tap without calling a plumber

A dripping tap is a permanent background hum of guilt. Every drip is a drip of water you paid to heat, a drip that's slowly staining the stainless-steel sink, a drip that's louder at 3am when you're trying to sleep.

Most drips are fixable in under an hour for under £15 in parts.

Diagnose the leak first

Watch the tap for a minute without touching it. Where's the water coming from?

• From the spout, dripping slowly after it's turned off: cartridge or valve. 90 percent of drips.
• From the base of the spout where it meets the body: O-ring, usually at the swivel joint.
• From the back, near the hose connections under the sink: compression fitting or hose connector. Often just needs a quarter-turn tighter.
• From around the tap where it's fixed to the sink surface: mounting seal, getting more annoying, bigger fix.

Isolate the water first. Seriously.

Most kitchen sinks have two small isolation valves under the sink, one for hot, one for cold. Look for a flathead screwdriver slot on a small valve on each hose. Turn 90 degrees. Open the tap above to confirm the water's off. If there are no isolation valves (common in older houses), turn off at the mains stop cock, which is usually under the kitchen sink or in the airing cupboard.

I've seen more than one DIYer take the top off a tap with the water still on. The result is the first scene in a small comedy. Don't do it.

The three fixes

Cartridge replacement (90% of drips)

Modern mixer taps use a ceramic disc cartridge. It's a small cylindrical unit inside the tap that controls flow. Cartridges wear out. They're cheap to replace. £5 to £15 depending on tap model.

The process:

1. Isolate the water.
2. Pop off the decorative cap on top of the tap handle (usually a little lever with a letter H or C, pry with a flathead).
3. Underneath is a screw. Undo it. Lift off the handle.
4. Unscrew the cartridge retaining nut. Careful, it's often tight.
5. Lift out the old cartridge. Take it to the plumbing merchant, or Amazon, and find the match. Brands: Reich, Kludi, Franke, Grohe, or generics that match the size.
6. Drop in the new one. Reassemble in reverse order.
7. Turn the water back on slowly. Check for leaks. Check the hot is actually on the hot side (easy to get this backwards).

45 minutes for someone who's done one before. 90 for a first-timer.

O-ring replacement

If the leak is at the base of the swivel spout, pull the spout upwards gently. It should lift off. Inside you'll see one or two small rubber O-rings. Replace with matching size from any plumbing merchant. £2. Smear of silicone grease on the new rings. Refit.

Tightening the connections

Under the sink, the flexi hoses connect to the tap with brass nuts. If they've loosened, a quarter turn tighter with an adjustable spanner (don't overdo it) stops a weep. If the hoses themselves are old and corroded, just replace them. A pair of new flexi hoses is £15.

When to get someone in

Most drips I fix in a single visit. The ones that genuinely need a plumber are:

• Old compression fittings under the sink that are seized solid. Risk of snapping a pipe.
• A tap where the base mounting has corroded into the sink. Sometimes the tap, the washer, and a chunk of sink all come out together.
• Any leak you can't isolate because the stop cock has also stopped working.
• Any installation where you need to change the hoses from one configuration to another (e.g., single flexi to dual flexi). Soldering or crimping territory.

Full tap swap

If the tap's had it and needs replacing:

• Pick a tap to match your sink holes (1-hole monobloc or 2-hole). Most modern kitchen sinks are 1-hole.
• Budget £80 to £200 for a decent tap. Franke, Grohe, Blanco, Reginox are solid. Avoid anything under £40, the cartridge will go within 18 months.
• Fitting time: 60 to 90 minutes including removing the old one and testing.

I'll supply and fit, or fit a tap you've already bought. Either's fine. What's less fine is finding out mid-install that the tap you've bought doesn't fit the hole, which happens often enough that I always ask to see the box before I commit to a visit.