Fix a Leaking Under-Sink Pipe — Kitchen
A leaking under-sink pipe in the kitchen is usually a worn seal or compression olive — a £3 fix caught early. Left unchecked it damages flooring, joists and ceilings below. Here is the trade method.
Step-by-step method
1. Isolate the water
Nearest isolator or property stopcock. Prove zero pressure by opening the under-sink pipe.
2. Dry and identify
Dry the under-sink pipe completely. Run 30 seconds. The first bead of water shows the exact fault.
3. Strip and inspect
Remove cover/collar. Inspect washer, O-ring, olive. Take to Screwfix/merchant to match.
4. Refit with new seal
Grease O-rings with silicone (not vaseline). PTFE-tape 5 wraps clockwise. Hand-tight + 1/4 turn.
5. Pressure-test
Open isolators, purge, run 60 seconds. Re-check after 24 hours.
Frequently asked questions
DIY or plumber?+
Non-gas leaks are DIY-friendly. Plumber callout £70–£140.
Emergency?+
Weeping = 24h. Active spraying = same day.
Insurance?+
Sudden damage yes; gradual leaks no.