How to Fix a Plumbing Leak

Introduction (why leaks matter and first signs)

Even a small drip can cause damp, ruin finishes, and push up water bills. In UK homes, common culprits are compression joints, push-fit connections, trap seals, toilet fill valves and flexible tap hoses. Act early: water tracks along joists and pipes, so the puddle you see isn’t always under the actual leak.

Find the source (systematically and safely)

1. Turn off nearby fixtures and wipe everything dry so you can spot fresh water.
2. Run one outlet at a time (hot then cold) and check joints, traps, hoses and valves above and below.
3. For toilets, add a little food colouring to the cistern; colour in the pan points to a weeping flapper/valve.
4. Check ceilings below bathrooms for brown rings or blistering paint — use a torch along coving and downlights.
5. If the stop tap or main incoming pipe is damp, you may have a supply leak; know where your stop tap is (usually under the kitchen sink or in a cupboard).

Electricity and water don’t mix. If you suspect water near electrics, isolate the circuit at the consumer unit and call a professional.

Safe temporary fixes (buy time, not a bodge)

• Dripping compression joint: Dry thoroughly and nip up the nut a quarter‑turn. Don’t overtighten. If it still weeps, remake with fresh PTFE or paste and olives.
• Split flexible hose: Isolate the tap’s service valve and replace the hose; do not tape over a split hose — it will fail again.
• Trap leak (under sinks/basins): Reseat the rubber washer, clean threads, and hand‑tighten. Replace perished washers as needed.
• Weeping toilet fill valve: Replace the diaphragm/seal kit; an easy, low‑cost part.
• Pin‑hole in copper: An epoxy pipe repair bandage can buy time, but arrange a section replacement soon after.

What affects price (access, parts, scope)

• Access and making good: Hidden leaks in walls/ceilings increase time and may require patching and redecorating.
• Parts: Flexible hoses, traps and valves are inexpensive; concealed shower valves, soil stacks or buried pipework cost more.
• Extent of damage: Drying out, dehumidifiers and mould remediation add costs if the leak has been ongoing.

Typical UK guides (ballpark):

• Minor joint/trap fix: £60–£120 labour plus small parts
• Tap hose/valve replacement: £80–£160
• Toilet internals (fill/flush): £80–£150
• Investigate hidden leak and repair: £150–£400 depending on access

DIY vs hire a pro (when to call)

DIY is sensible for exposed traps, tap hoses and toilet internals if you can isolate water and work tidily. Call a plumber if:

• You can’t isolate the local supply or the stop tap is seized
• The leak is within walls, floors or near electrics
• Mains/stopcock, unvented cylinders, or sealed heating systems are involved
• You need pipe soldering, soil stack work, or making good

Prevention (small habits, big wins)

• Inspect flexible hoses every 6–12 months and replace at first sign of bulge/corrosion.
• Fit isolation valves when doing any tap/fixture work.
• Don’t overtighten plastic traps; keep spares for washers and diaphragms.
• In hard‑water areas, descale aerators and shower heads to protect seals.

Next steps (quick checklist)

1. Find and isolate the source; protect electrics and soft furnishings.
2. Attempt a safe temporary fix (or replace simple parts) if confident.
3. Photograph damage for insurers if relevant.
4. Book a local plumber for concealed or persistent leaks — earlier is cheaper.