A removable sink P-trap is cleaned by disconnecting it, emptying the stagnant water and debris, scrubbing it, correctly refitting its seals and leak-testing both joints. In NSW, disconnecting and reconnecting sanitary plumbing may require an appropriately licensed plumber, so householders should limit themselves to preparation and observation unless current NSW guidance confirms otherwise.
The P-trap is the curved or U-shaped waste pipe under the sink that retains a water seal. These steps apply only to removable compression-joint traps.
Prepare the Area
Stop using the sink and any connected dishwasher. Clear the cabinet, place a bucket and towels under the trap, and wear waterproof gloves and eye protection.
A plumber will generally need a bottle brush, warm water and mild detergent. Pliers may be used carefully over a cloth if a compression nut will not turn by hand, but brittle plastic fittings must never be forced.
Do not open the trap if caustic drain cleaner may be present. Avoid contact and tell the plumber which product was used and when. For suspected poisoning or chemical exposure, call the Poisons Information Centre on 13 11 26.
Without moving the trap, check whether it is glued, cracked, corroded or difficult to access. Stop and use a licensed plumber if it is damaged, fixed in place or moves adjoining pipework when touched.
Cleaning and Leak-Testing
Disconnect the trap: The plumber supports the adjoining pipework, positions the bucket underneath and loosens both compression nuts without placing strain on the pipes.
Empty and clean it: The trap is lowered into the bucket and emptied. Solid debris goes in the rubbish, not another drain. The inside is scrubbed with warm water, mild detergent and a bottle brush, then rinsed.
Inspect the components: Nuts and washers are kept in their original order. Cracked plastic, damaged threads, distorted washers or perished seals must not be refitted.
Reassemble it: Washers are returned in the orientation specified by the trap manufacturer. The joints are aligned without pulling the pipework sideways and tightened as directed. Thread tape is generally unsuitable for compression joints because the washer forms the seal.
Leak-test both joints: With the bucket still underneath, the plumber dries the joints, runs the tap and then releases a partly filled basin. Dry tissue held against each connection can reveal slight moisture.
If a joint drips, stop the water rather than aggressively tightening a plastic nut. Contact our licensed Sydney plumbing team if the trap remains slow, leaks persist or any component is damaged.