Step 6 · Final Tightening and Testing for Leaks
With all components in place, perform the final tightening. Re-check and tighten each slip nut connection: where the tailpiece meets the J-bend, where the J-bend meets the trap arm, and where the trap arm enters the wall drain. First, ensure they are all fully hand-tightened. Then, use channel-lock pliers to give each nut a final quarter-turn. Do not apply excessive force. Place the bucket back under the newly installed P-trap. Open the water shutoff valves fully. Turn on the faucet and let lukewarm water run for at least a minute. Operate the pop-up stopper to ensure it functions correctly under water flow. While the water is running, carefully inspect every joint, nut, and seal for any sign of dripping. To perform a stress test, close the stopper, fill the sink basin completely, then open the stopper to release a large volume of water at once. This tests the seals under maximum flow. Check again for leaks. Once satisfied, wipe the entire assembly dry with a rag and place a dry paper towel underneath for 10-15 minutes as a final, sensitive check for slow drips.