Replace a leaking sink P-trap
Fit a matching rigid trap, align its seals and check every joint under a full drain flow.
Home · 1–2 hr · Medium
Before you start
Keep the sink out of use during work. Do not open a drain containing chemical drain cleaner; obtain safe handling advice first. Wear gloves and eye protection for dirty trap water. Close the sink’s supply valves if needed to prevent accidental use, but do not force seized valves. Stop if the wall connection is loose, corroded or damaged.
Tools and materials
- Matching rigid tubular P-trap kit with its specified nuts and washers
- Bucket, absorbent cloths, gloves and eye protection
- Tape measure, marker, fine-tooth saw and deburring tool for permitted tube trimming
- Slip-joint pliers for loosening stubborn nuts, with protective cloth
Check the problem
Locate the actual leak
Dry the pipes, then run a little water and watch from the highest joint downward. A leak above the trap can track along it. A cracked bend needs replacement; a sound joint may only need a correctly seated matching washer. Stop the flow before inspecting closely.
Match the connections before buying
Measure the tubular drain size and photograph the assembly. Buy a compatible kit that reaches the existing wall adapter without strain. Do not assume a plastic and metal trap use interchangeable seals. If the drain drops through the floor or needs rerouting, this is not a like-for-like swap.
Steps
Clear the cabinet and catch the water
Keep everyone from using the sink. Put a bucket under the bend and towels around it. Photograph the nut and washer locations before undoing anything.
Undo the nuts and lower the trap
Support the bend while loosening the removable nuts. Use gentle tool pressure only if hand loosening fails, without twisting the wall pipe. Lower the bend into the bucket and empty it. Remove the old sealing washers from the connections being renewed.
Clean the mating surfaces
Wipe away residue and inspect the tailpiece and wall adapter for cracks, distorted threads or corrosion. Do not tighten a new trap onto a damaged connection. Keep debris out of the open drain and avoid leaving it open unnecessarily.
Measure, trim and deburr if needed
Dry-fit the kit without forcing its alignment. Mark only the straight tube end the kit permits you to shorten. Remove it, cut square and smooth both cut edges. Keep enough insertion at each joint; do not let a tube bottom out and block the passage.
Place each nut and seal correctly
At a tapered slip-washer joint, slide the nut on first, then the washer with its narrow bevel facing the receiving fitting. Use the kit’s specified seal at the bend-to-arm union; some seal on shaped mating faces without a separate washer. Do not add thread tape or glue.
Connect without pulling pipes sideways
Insert the wall arm and connect the bend beneath the tailpiece in its intended orientation. Start all nuts straight by hand before final tightening. Keep the trap upright and the arm correctly aligned toward the existing wall drain; never invert the bend to make it reach.
Tighten as specified and test under flow
Follow the kit’s tightening directions; excess force can split plastic. Restore any closed supply valves. Run water, then fill and release the basin while watching every joint. Dry tissue reveals tiny leaks. If one persists, stop and reseat or replace its seal instead of repeatedly overtightening.
All joints remain dry during faucet flow and a full-basin drain; drainage is free and the assembly is unstrained.
Tips
The washer does the sealing
Thread tape cannot fix a missing, reversed or damaged slip-joint washer.
Use rigid parts that align
Do not force misaligned tubes together or use corrugated tubing to hide a layout problem.
Recheck after the next use
Leave the cabinet clear for a final inspection after normal sink use.