Step 4 · Connect Water Supply Lines and Drain
Now, make the final plumbing connections. First, attach the new flexible water supply lines to the threaded tailpieces on the bottom of the faucet. Hand-tighten these connections, then give them a quarter-turn with an adjustable wrench. Connect the other ends of the supply lines to the corresponding hot and cold shutoff valves. Again, hand-tighten and then give a quarter-turn with the wrench. Next, assemble the P-trap. Connect the tailpiece coming down from the sink drain to the P-trap U-bend, and the trap arm to the drain pipe in the wall. You may need to cut the PVC tailpiece or trap arm to the correct length with a hacksaw or tubing cutter. Ensure all slip nuts have their tapered plastic washers oriented correctly (taper facing the direction of the seal) before tightening. Hand-tighten all the P-trap slip nuts; they do not need a wrench.