Fix a Leaky Faucet: Step-by-Step Guide

Understanding Common Faucet Leak Types

Faucet leaks come in several varieties, and identifying which type you have is the first step toward fixing it. The most common leak is a dripping faucet, where water falls from the spout one drop at a time, even when the handle is fully turned off. This type of leak typically wastes about 3,000 gallons of water annually—enough to fill a small swimming pool. Another frequent problem is a leak from beneath the sink, which indicates water is escaping from the connection points or internal plumbing rather than from the spout itself. Some faucets leak from around the base where the spout connects to the sink, suggesting the seals have worn down. Handle leaks occur when water drips from around the handle when you turn it, pointing to deterioration in the handle assembly itself.

Understanding the leak location matters because it determines which repair approach you'll need. A dripping spout usually requires replacing internal washers or seals, while a leak from beneath the sink might mean tightening connections or replacing supply lines. Base leaks often need the entire faucet cartridge replaced, depending on whether you have a single-handle or double-handle model. Single-handle faucets use a cartridge mechanism, while double-handle faucets typically rely on separate washers and valve seats for each handle. Before you begin any repair, turn off the water supply valves located beneath the sink—you'll find two shut-off valves, one for hot water and one for cold water. Turn them clockwise until they stop. Then turn on the faucet to release any remaining water pressure in the lines.

Practical takeaway: Spend a few minutes observing where your faucet leaks and what type of faucet you have. Photograph the area under the sink so you can show it to a hardware store employee if you need parts identification help. This information will save you time and money when purchasing replacement components.

Gathering Your Tools and Materials

You don't need a professional plumber's full toolkit to fix most leaky faucets. A basic repair kit costs between $15 and $40 and includes items you may already own. Essential tools include an adjustable wrench (to fit various bolt sizes), a screwdriver set with both flathead and Phillips head options, pliers for gripping and bending, and a flashlight for seeing under the sink. A hex key or Allen wrench set proves helpful for faucets with set screws. Keep a bucket or towel nearby to catch residual water from the pipes—don't be surprised if a quart or more of water spills out. Many people overlook this detail and end up with water on their cabinet floors.

For replacement parts, you'll likely need washers, O-rings, and possibly a cartridge or valve seat, depending on your faucet type. Washers are small rubber or plastic discs that wear out over time and cost under $5 for a variety pack. O-rings are rubber seals that prevent water from leaking around connections—these typically cost $2 to $8. If your faucet is older or heavily used, you might need a complete cartridge replacement, which ranges from $20 to $75. Visit your local hardware store with a photo or sample of your faucet to ensure you purchase compatible parts. Store employees can usually identify your faucet model from a picture of the handle and spout configuration. Some hardware stores offer free identification services because matching the wrong parts leads to return visits and frustrated customers.

Before shopping, check whether your faucet has identifying markings. Look for manufacturer logos on the spout or base—common brands include Moen, Delta, Kohler, and Pfister. Write down any model numbers you find. This information makes parts selection straightforward and prevents buying items that won't fit your specific faucet model.

Practical takeaway: Assemble your tools in one location before starting work. Create a small workspace under the sink with your bucket, towel, flashlight, and tools arranged within arm's reach. This prevents frustration from hunting for items mid-repair and keeps water damage contained.

Repairing a Dripping Single-Handle Faucet

Single-handle faucets use a cartridge—a small cylindrical component that controls water flow and temperature. When water drips from the spout, the cartridge seals have usually worn out. Begin by turning off the water supply valves beneath the sink, then opening the faucet fully to release pressure. Next, remove the handle by locating the set screw, which is typically hidden under a decorative cap. Pop off this cap with a flathead screwdriver, then unscrew the set screw with an Allen wrench or screwdriver. Pull the handle straight upward to remove it. Some handles simply slide off after removing the screw, while others require gentle wiggling.

With the handle removed, you'll see the cartridge nut—a large hexagonal bolt holding the cartridge in place. Use your adjustable wrench to turn this nut counterclockwise. You'll likely need significant force if the nut hasn't been removed in years. Once loosened, unscrew it by hand. Pull the cartridge straight out using pliers if it resists. Water may still drip from inside the faucet body, so keep your bucket underneath. At the hardware store, bring your cartridge or faucet photos to ensure you purchase the correct replacement cartridge. Install the new cartridge by sliding it into the faucet body with the flat edge of the cartridge aligned with a flat edge inside the faucet body—this orientation ensures proper water temperature control.

Reinstall the cartridge nut and tighten it firmly with your wrench. Don't over-tighten, which can crack the ceramic components inside. Replace the handle by sliding it back onto the cartridge shaft, then install and tighten the set screw. Replace the decorative cap. Turn the water supply valves back on slowly, starting with cold water. Check for leaks around the handle and base. If water drips from the spout when the handle is fully off, the cartridge wasn't seated properly. Turn off the water again and remove the cartridge to verify proper alignment.

Practical takeaway: Mark the orientation of your old cartridge before removal by placing a piece of tape on both the cartridge and faucet body in matching positions. This visual guide makes reassembly alignment obvious and reduces the chance of installing the cartridge backward.

Repairing a Dripping Double-Handle Faucet

Double-handle faucets function differently than single-handle models. Each handle controls a separate valve, with washers and valve seats doing most of the water control work. When a double-handle faucet drips, it typically means a washer has deteriorated or the valve seat has become scratched. Start by turning off the water supply beneath the sink, then remove the handle that corresponds to the dripping water—if cold water is dripping, work on the cold water handle. Look for a set screw on the back of the handle or under a decorative cap on top. Remove this screw with the appropriate screwdriver.

Pull the handle straight upward to remove it. You'll now see the packing nut—a hexagonal bolt beneath where the handle was. Use your adjustable wrench to turn this nut counterclockwise. Once loose, unscrew it by hand. Beneath this nut is the valve stem, which you should grasp with pliers and turn counterclockwise to remove it completely. When you pull out the valve stem, you'll see a small rubber washer on the bottom end. This washer is almost certainly worn out and causing your leak. It's a simple disc, typically about the size of a pencil eraser. Take it off and bring it to the hardware store to purchase an exact replacement, or buy a variety pack of washers in common sizes.

While you have the valve stem out, inspect the valve seat—the metal or ceramic surface where the washer sits. If it feels rough or has visible scratches, you can smooth it with a valve seat dresser tool (a specialized tool that costs about $10), or you can replace the entire valve seat with a new one using a valve seat removal tool. For most homeowners, simply replacing the washer solves the problem. Install the new washer by placing it in the recess on the valve stem bottom, then reinsert the stem into the faucet body. Turn it clockwise until it stops—don't force it or you'll damage the new washer. Reinstall the packing nut, handle, and decor