Final Drain Tightening and Leak Test

What happens here

Once the disposal and P-trap are loosely connected, begin tightening all compression nuts on the P-trap connections (disposal to P-trap, and P-trap to ABS adapter). Tighten by hand first, then use channel lock pliers to give each connection a final snug tightening. The presenter advises against overtightening, as plastic can crack. Next, ensure the drain plug on the disposal's side port (where the dishwasher drain line would connect, if applicable) is still in place to prevent leaks. Fill the sink basin completely with water. Once full, remove the sink stopper and let all the water drain through the disposal and P-trap. While the water is draining, carefully inspect all new plumbing connections (faucet supply lines, disposal mount, P-trap connections) for any signs of leaks or drips. If any leaks are found, tighten the affected connection slightly and re-test. Once the sink drains completely and there are no leaks, the installation is complete.

Goal: All drain connections are fully tightened, and a final leak test is performed to ensure the entire system is watertight.