Always be sure to shut off the water before your repairs, or else it will spray all over your bathroom. If you can’t find the supply valves underneath your sink, you can always shut off the main supply valve where the water supply pipe connects to your home.

If you don’t have a stopper, you can instead put a rag or towel on the bottom of your sink. This also helps protect your sink’s finish in case you drop parts or tools.

The decorative cap hides the set screw that secures the handle to the actual faucet. If you can already see a screw on your faucet, then you do not need to remove the decorative cap.

Most times, you won’t need to remove the set screw completely from the handle.

Line the parts of your faucet up on a towel in the order you removed them so you remember how to put it back together. Be careful not to damage the finish on the metal cap. If you’re worried about scratches, wrap some electrical tape around the ends of your pliers before using them. [7] X Expert Source Dave JonesMaster Plumber, Roto-Rooter Plumbing & Water Cleanup Expert Interview. 29 March 2021.

Faucet cams usually cost around $5 USD. If that was your only leak, you can put your faucet back together and turn the water back on to see if you fixed your issue. Otherwise, set the cam aside for now.

The residue on the ball prevents the faucet from closing completely and could be the cause of your leak.

Seal and spring replacement kits usually cost between $5–10 USD. The springs and seals control the flow of hot and cold water through your faucet.

A set of O-rings tend to cost around $2–5 USD. Plumber’s grease helps form a watertight seal, and you can buy it from your local hardware store.

You don’t have to put the handle before you test your faucet if you don’t want to. That way, there’s one less piece you have to take off if your faucet still leaks.

If there aren’t any leaks and you haven’t put on the handle yet, just put the handle back on the lever and tighten the set screw. The decorative cap should pop right back into the handle.

If there’s a decorative metal finish on the nut, put electrical tape on the ends of your tools to prevent them from leaving scratches. Instead of a nut, the cartridge may have a staple-shaped clip that slides into the side. Grab the end of the clip with a pair of pliers and pull it straight out. [16] X Research source

If the cartridge is stuck inside your faucet, you may need a special removal tool to get a better grip. You can buy one from your local hardware store.

O-rings usually cost around $2–5 USD. When you have a damaged seal, water could leak through it and cause your leak in the base or spout of your faucet.

Faucet cartridges vary depending on the model, but they usually range from $15–30 USD. Many faucet manufacturers offer online guides to help you match your faucet to the correct parts even if you can’t find the model number.

If you still see a leak, then contact a plumber to find the source.