Replacing a copper tap requires a skilled installer to complete the job. The process may take 1.5 to three hours for a plumber to complete. It also depends on the type of sink, the age and condition of your plumbing, and whether or not your sink has a garbage disposal. Depending on the type of kitchen faucet and the difficulty of installation, a plumber may need to remove the old faucet or make changes to the plumbing system. If you have a stone countertop, you should be sure to choose the correct type of faucet.