Domakihub Replace a Kitchen Sink P-Trap Without Leaks
A corroded or cracked P-trap is a quick fix — if you use the right PVC fittings and seat every joint correctly.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 4 min read
A leaking or foul-smelling kitchen drain is one of the most common maintenance calls in Greek homes, holiday villas, and hotel kitchens alike — and a failed P-trap is the culprit far more often than people expect. The video above walks through the replacement visually; this article pairs those steps with the specific slip-joint sizes used in Greek PVC plumbing and the details that prevent the job from leaking the first time. Whether you manage a single apartment or a portfolio of rental properties, replacing a P-trap takes under thirty minutes and requires no special tools.
Why the P-Trap Fails and When to Act
The P-trap is the curved section of pipe directly beneath your kitchen sink. It holds a small reservoir of water that physically blocks drain gases — hydrogen sulphide and methane — from entering the room. In Greece, where many properties sit in coastal or high-humidity climates, plastic traps can become brittle from UV exposure under open-plan kitchens, and chrome-plated brass traps corrode through within a few years when exposed to aggressive cleaning chemicals.
Replace the trap immediately if you see visible cracks, white mineral deposits weeping from a joint, or if the kitchen smells of drain gas even after cleaning. A slow drip that leaves a water stain on the cabinet floor is also a clear sign the slip-nut seals have failed and tightening alone will not save them.
Choosing the Correct Fittings for Greek Plumbing
Greek residential plumbing almost universally uses 40 mm (1½-inch) drain outlets at the sink strainer, which corresponds to the standard P-trap sold at any Greek builders' merchant (χρωματοπωλείο or υδραυλικά). Confirm the measurement before buying: hold a tape across the outside of the existing pipe where it enters the wall stub-out. If the stub-out is 50 mm, you need a reducing washer or a stepped adapter — both are sold alongside the trap kits. For vacation rentals and commercial kitchens with double-bowl sinks, buy a trap arm extension (κάλυμμα σιφόν) long enough to reach the wall without stressing the joint.
Stick to white or grey PVC slip-joint trap kits rather than chrome brass for new installations. PVC resists the limescale-laden water common in the Aegean islands and mainland Greece, is easier to hand-tighten correctly, and costs a fraction of the price. The kit typically includes the U-bend, a straight trap arm, two slip nuts, and two flat neoprene washers — everything you need.
How to Replace a Kitchen Sink P-Trap: 5 Steps
- 1
Cut the water and clear the cabinet
You do not need to shut off the water supply to replace a P-trap, but place a bucket or an old towel directly under the existing trap before you touch anything. The U-bend holds standing water and residual food debris; having the bucket in place means you avoid a puddle on the cabinet floor. Remove any items stored under the sink so you have room to work with both hands.
- 2
Unscrew the slip nuts and remove the old trap
Locate the two slip nuts — one where the trap meets the sink drain tailpiece and one where the trap arm enters the wall stub-out. Hand-loosen both counter-clockwise. If they have not moved in years, use slip-joint pliers with a cloth wrap to avoid cracking aged plastic. Once loose, slide the nuts back along the pipe, then pull the whole U-bend and arm section free. Let it drain into the bucket, then wipe the tailpiece and stub-out openings clean.
- 3
Dry-fit the new trap before committing
Slide the new slip nuts onto the tailpiece and stub-out arm with the threaded ends pointing toward the trap, then position the new P-trap in place without tightening anything. Confirm the trap arm runs slightly downhill toward the wall (a drop of about 6 mm per 30 cm is ideal). If the arm is too long, cut it with a fine-tooth hacksaw or a PVC pipe cutter so the joint inside the stub-out is solid, not resting on the cut end. This dry-fit step catches sizing problems before the washers are compressed.
- 4
Seat the washers and hand-tighten the nuts
Place a flat neoprene washer inside each slip nut with the tapered side facing into the fitting — the taper compresses against the pipe to form the seal. Thread each nut clockwise by hand until it is firmly snug. The critical rule here is hand-tight only: over-tightening with pliers distorts the washer and creates the very leak you are trying to prevent. Once hand-tight, add no more than a quarter-turn with pliers if the connection still feels loose, and stop there.
- 5
Test with a full flow and check every joint
Run the cold tap at full pressure for 30 seconds while watching both slip-nut joints from below. Run a dry sheet of tissue paper around each joint — any moisture shows immediately. Then fill the sink basin completely and release the stopper so the trap sees surge flow, not just trickle. If a joint seeps, drain the water, hand-loosen the nut, re-seat the washer so it sits evenly, and re-tighten. A correctly seated neoprene washer seals reliably without sealant or thread tape.
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FAQ
- Do I need to use plumber's putty or Teflon tape on slip-joint connections?
- No. Slip-joint P-trap fittings seal with the neoprene flat washer, not with compound or tape. Applying Teflon tape to a slip nut thread can actually prevent the nut from tightening fully and makes the washer seat unevenly. Use tape only on threaded connections such as the strainer body or a threaded wall adapter, never on slip joints.
- My replacement trap still drips at the wall stub-out — what is wrong?
- The most common cause is a damaged or missing rubber gasket inside the wall fitting rather than a problem with the new trap itself. Remove the trap arm, inspect the stub-out opening for cracks or a hardened old gasket, and replace the gasket if present. If the stub-out is threaded rather than a slip fitting, wrap the male threads with two layers of PTFE tape before re-inserting the arm.
- What trap size do I need for a Greek kitchen sink?
- Almost all Greek residential kitchen sinks use a 40 mm (1½-inch) drain outlet. Measure the outside diameter of your sink tailpiece before buying. Some older properties — especially those built before 1990 — may have a 32 mm outlet, in which case you need a 32-to-40 mm reducing washer or a purpose-made 32 mm trap kit. Double-check by dry-fitting the slip nut before purchasing the full kit.