Modern faucets are designed to provide years of trouble-free service. In busy households, a kitchen sink faucet is used many times a day, by all members of the family. Over time, the parts in the faucet can become brittle and wear out. A leak around the base of a kitchen faucet is usually caused by worn out O-ring seals located under the faucet spout. Replacing these O-ring seals can add years to the life of the faucet.
Turn off the water supply to both the hot and cold sides of the faucet.
Close any drains to prevent the loss of dropped faucet parts.
Pry the plastic cover off the top of the spout using a flat screwdriver. If the faucet is a single lever type, you will need to remove the faucet handle before the spout. The handle will be attached either by a Philips screw in the top or by a hex head screw in the side of the handle.
Remove the retaining nut from the top of the spout by using the water-pump pliers or a wrench to turn the nut counterclockwise .
Grasp the spout, and while twisting back and forth, pull the spout up and off the faucet body.
Remove the O-rings from the faucet body using the needle-nose pliers. Usually, there are at least two O-rings, but there could be three or even four. The O-rings should be easy to see and locate.
Slip the replacement O-rings onto the faucet body, being careful to place the O-rings within their grooved slots, and make sure that the O-rings are not twisted.
Apply faucet lubricant to the outer edges of the O-rings and re-install the spout and the spout retaining nut.
Reinstall the handle and screws and the plastic decorative covers in the reverse of the order you removed them.
Open any drains you've closed, and turn on the water supply to the faucet. Turn on the faucet, twist the spout from side to side and check for any leaks around the base.