Step 7 · Test for Leaks and Apply Caulk
With all connections made, it's time to test your work. Place a dry rag or paper towel under each connection point to make leaks easier to spot. Turn the shutoff valves on slowly, starting with cold then hot. Carefully inspect the supply line connections at both the valve and the faucet for any drips. Turn the faucet on and let the water run. Check all the P-trap connections for leaks. Fill the sink basin completely with water, then release the pop-up drain. Watch the entire drain assembly for leaks as the large volume of water flows through. If you find a small leak, try tightening the connection slightly. Apply a thin, neat bead of kitchen and bath silicone caulk around the base of the pedestal where it meets the floor, and also along the back edge of the sink where it meets the wall. Smooth the bead with a wet finger.