Whether it’s the annoyance of a persistent drip or water pooling around your faucet handles, the cause is a leaky faucet. Here are a few easy steps to fix it.
1) Assemble the necessary tools. For this task, you will need:
- Pliers, adjustable wrench, or Allen wrenches
- Calcium remover
- Needle nose pliers
- Utility knife
- Faucet replacement parts
2) Shut off the water. Go underneath the sink and turn off the water valves (typically, turning the knobs to the right will close the valves). Then try turning the faucet handles. If the flow stops, you’ve properly turned the water off and can start inspecting.
3) Inspect the handles and cartridges. Many faucet leaks are handle-related. Pop off the cap over the handles and/or unscrew them from the faucet. Within the handle there are many parts including seals, washers, o-ring, and the stem. Inspect them for cracking and general wear and tear. Each of these individual parts can be replaced without buying brand new handles.
To replace the cartridge, remove the old one with a pair of pliers. There may be a screw or nut holding it in place. Push in the new cartridge and tighten it back into place.
Pro Tip: bring the old parts to the hardware store to ensure proper sizes.  If you have an older faucet, local hardware stores will be your best bet; they tend to carry older style models in-store or can place special orders for replacement parts.
4) Clean with Calcium Remover. Before you fully reassemble the faucet, clean any scaly parts with calcium remover or a plumbing-safe solvent. This will prevent further damage to the faucet parts.  Safety tip: be sure to wear gloves when using any chemical cleaners.
5) Reattach Faucet Parts. Make sure each piece from the handle is assembled correctly and tightly and then turn the water back on to see if there is still a leak. Be sure to test both the hot and cold water separately. If you are still experiencing leaking or dripping, it’s time to call in a professional.
A couple of quick notes for leaks on different types of faucets:
Compression faucets have separate handles to control the hot and cold water. When leaks happen with compression faucets, typically it’s the washers or o-rings that need to be replaced. Washers can be found inside the handles by unscrewing the packing nut and then the stem. O-rings are located underneath the washer.
Ball Type and Cartridge Faucets
With their long adjustable pressure/temp handles, individual parts are more difficult to fix on these intricate faucets and may require a special kit. You will need needle-nose pliers to inspect and potentially remove inlet seals and springs. O-rings may have to be cut with a utility knife to be replaced.
These high-quality valves can be identified by a single lever above a broad cylindrical body. Ceramic-disk faucets have a wide cartridge that houses two ceramic discs. Like all other faucets, first remove the handle from the actual faucet. Unscrew the disk cylinder mounting and lift out the cylinder. Find the seals on the cylinder and replace them if they are worn, then clean with white vinegar.