Pipe Leaking: Causes, Checks & Fixes

Stop the water first and keep it away from electrics

Use the nearest safe isolation valve or main stopcock. If water is reaching sockets, lights, appliances or the consumer unit, keep clear and isolate the affected electrical circuit only if it is safe to do so.

MOST LIKELY CAUSES

Start with these

Split or punctured pipe Freezing, impact, screws or drilling can damage pipework.

Corrosion or pinhole leak Older copper and steel pipe can develop local failures.

Nearby joint leaking Water may track along the pipe before dripping.

Pressure or movement fault Water hammer, expansion and poor support can strain pipework.

◫ Symptom variations Match when and where the leak appears. ⌄

Visible drip or spray from pipe
Damp patch below a concealed pipe
Leak worsens when a tap is used
Leak stops when heating cools
Water tracks along pipe before dripping

✓ Quick checks Simple checks before dismantling anything. ⌄

Dry the area so fresh water reveals the true source.
Check whether the leak is constant or only appears during use.
Identify whether the water is clean supply water, heating water or waste water.
Close the nearest service valve or main stopcock if the leak is pressurised.
Protect floors, cabinets and electrical equipment from further water.

If the leak stops: keep the source isolated until a lasting repair is made.

If water continues: check tanks, heating circuits, shared supplies or call a plumber urgently.

1 Step 1 — Isolate the water Follow this check before dismantling plumbing. ⌄

Process

Close the relevant service valve or main stopcock and open a low tap to relieve pressure.

Success looks like: The leak slows or stops.

Escalate when: If water continues, a tank, heating circuit or separate supply may be feeding it.

2 Step 2 — Contain the water Follow this check before dismantling plumbing. ⌄

Process

Use towels, trays and temporary protection to limit damage.

Success looks like: Water is directed away from electrics and finishes.

Escalate when: Do not rely on containment as the repair.

3 Step 3 — Identify the exact failure point Follow this check before dismantling plumbing. ⌄

Process

Dry the pipe and observe where fresh water first appears.

Success looks like: The damaged section or joint is confirmed.

Escalate when: If concealed, professional tracing may be needed.

⌁ Common causes explained Why these leaks develop. ⌄

A leaking pipe may be split, corroded, frozen, damaged by drilling or leaking from a nearby joint. The first priority is to stop the water and protect the property.

Water often travels along pipes, cabinets, joists and surfaces before it drips. The visible wet patch may not sit directly below the actual failed joint or fitting.

⌘ Advanced diagnostics Plumber-level checks and repair work. ⌄

Pressure-test the affected section.
Inspect pipe supports and movement points.
Check for corrosion, freezing or mechanical damage.
Cut out and replace damaged pipework.
Verify the repair under full operating pressure.

▣ Parts that may need replacing Common components linked to this leak. ⌄

Replacement pipe section
Repair coupling
Pipe clips
Isolation valve
Insulation
Suitable joint fittings

! When to call a plumber Conditions that should end basic troubleshooting. ⌄

The leak cannot be isolated.
Water is reaching electrical equipment.
The leak is concealed inside a wall, ceiling or floor.
A ceiling is bulging, sagging or unsafe.
A main stopcock, buried supply or heating circuit is involved.
The leak returns after a minor adjustment.

? Frequently asked questions Common questions about plumbing leaks. ⌄

Why does the drip appear away from the damaged joint?

Water can track along pipes and surfaces before falling at a lower point.

Should I keep tightening a leaking nut?

No. Over-tightening can distort olives, seals and fittings and make the leak worse.

Can a small drip cause serious damage?

Yes. Slow leaks can damage cabinets, ceilings, flooring and hidden timber over time.