First: Know Where the Shut-Offs Are

Before any of the specific jobs below, do the one piece of preparation that matters more than all of them: find the main water shut-off valve, the consumer unit or breaker panel, and — if you have gas — the gas shut-off. Then check the water valve actually turns. Valves that have not moved in fifteen years seize, and discovering that during a leak is the worst possible time.

While you are there, find the isolating valves on individual fittings. Most modern taps and toilets have a small in-line valve on the supply pipe, usually with a slot for a screwdriver, that shuts off just that fitting. A quarter turn so the slot sits across the pipe means closed.

A Dripping Tap

A tap that drips is losing a surprising volume of water over a month and staining the sink while it does it. The repair depends on which of the two types you have.

Traditional taps with a rubber washer turn several times from off to on and get harder to close as they age. The washer at the bottom of the spindle has hardened or split. Replacement is a genuinely simple job: isolate the water, open the tap to drain it, prise off the decorative cap on the handle, remove the screw underneath, lift the handle off, unscrew the headgear with a spanner, and the washer is on the base — held by a small nut or simply pushed on. Take the old one to the shop rather than guessing the size.

Quarter-turn taps with ceramic discs move ninety degrees from off to on and have no washer. Two polished ceramic discs slide across each other, and when one chips or the grit in the water scores it, it drips. You replace the whole cartridge rather than a washer. They come in different sizes and thread patterns; take the old one out first and match it.

If the drip is from under the handle rather than the spout, that is the O-ring on the spindle, not the washer, and it is a similarly cheap part.

Before any of this, put the plug in the sink. The small screw you drop will otherwise go down the drain, and that turns a fifteen-minute job into a very different afternoon.

A Running Toilet

A cistern that trickles constantly wastes an enormous amount of water — often more than every other leak in the house combined. There are two possible causes, and telling them apart takes one minute.

Lift the lid and look at the overflow — either a pipe going out through the wall on older systems, or an internal standpipe.

If water is running into the overflow, the fill valve is not shutting off. Either the float is set too high, in which case adjusting it down so the water stops around 25mm below the overflow solves it, or the fill valve itself has failed and needs replacing. Fill valves are inexpensive and screw into the base of the cistern with a single large nut.

If the water level is fine but water is still moving in the pan, the flush valve seal at the bottom of the cistern has perished — a rubber diaphragm or a seal on a drop valve. This is the more common cause on modern dual-flush systems, which are notorious for it. Replacing it means isolating the supply, draining the cistern, and in most designs lifting the whole flush mechanism out from inside, which usually requires removing the cistern from the wall on close-coupled units. It is not difficult, but it is a job with a bucket in it.

The dye test, if you are unsure: a few drops of food colouring in the cistern, no flushing for thirty minutes. Colour appearing in the pan means the flush valve is leaking.

A Slow or Blocked Drain

Work up in order of aggression, and note that chemical drain cleaners are the last resort, not the first — they are hazardous, damage some pipework and seals, and if they fail you now have a blocked drain full of caustic liquid that the next method has to deal with.

  1. Boiling water down the plughole, for grease in kitchen sinks.
  2. A plunger, with the overflow held closed with a wet cloth — otherwise you are just pushing air out of the overflow instead of pressure down the pipe.
  3. Clean the trap. The U-bend under the sink unscrews by hand on most modern plastic waste fittings. Bucket underneath, unscrew both collars, remove the trap, clear it, refit. This is where the blockage is roughly three quarters of the time, and it is a five-minute job.
  4. A drain snake or hand auger for anything further along.

For a bathroom basin or shower, the blockage is nearly always hair, and it is nearly always within reach of the plughole with a piece of bent wire or a cheap plastic drain strip.

A Sticking or Dropping Door

Doors bind for a small number of reasons, and the right fix depends on which.

Check the hinges first. Grip the door edge and lift; movement means loose hinge screws or a worn hinge. Tighten the screws — and if a screw just spins, the hole in the frame has worn out. The old repair works perfectly: glue several matchsticks or a slim wood offcut into the hole, let it set, cut flush, and drive the screw again into fresh timber. A longer screw that reaches into the frame stud behind is also effective.

If it binds only in wet weather, the timber has swollen and will very likely shrink back. Wait before cutting anything. Sealing the top and bottom edges of the door with paint or varnish — the edges that are usually left bare — reduces this considerably.

If it binds constantly, find where. Slide a piece of paper down the gap to locate the tight point. Rubbing at the top of the latch side usually means the door has dropped and the hinges need attention rather than the door needing planing. Only when the hinges are sound and the door still binds is planing the answer, and then you take off very little, from the hinge side where possible, and repaint the bare edge.

A latch that no longer catches usually means the strike plate on the frame is a couple of millimetres out. Look for the shiny witness mark the latch has worn on the plate. A small adjustment — filing the plate opening, or unscrewing it and moving it — is the fix.

Squeaking hinges take a drop of oil on the pin, or a smear of grease, and thirty seconds.

Small Wall Damage

Nail and screw holes and hairline cracks take ready-mixed filler. The technique matters more than the product: press it in properly with a flexible filling knife rather than smearing it on, leave it very slightly proud, let it dry fully, and sand flush with fine paper wrapped around a block — not with your fingers, which round the surface into a visible dish. Two thin applications beat one thick one, which shrinks and cracks.

A hole in plasterboard up to fist size needs backing before filler, because filler alone has nothing to sit on. A self-adhesive aluminium mesh patch over the hole, then two or three thin coats of filler feathered well outside the patch, sanded between coats, disappears entirely under paint.

Anything larger wants a proper cut-out-and-replace: square off the hole, fix a timber batten inside behind the edges, screw in a matching piece of plasterboard, tape the joints, then fill and feather.

Always prime filler before painting. Filler is more absorbent than the wall around it and paint dries differently on it, so unprimed patches show as a dull shadow through the finish coat — the mark of a repair that everybody in the room can see.

Know What Is Not on This List

Nothing here involves gas, mains wiring, or structure — and that is deliberate. Those are covered in the next guide, along with the reasoning about where the line is.