How to Repair a Leaking Faucet: Tools, Step-by-Step Fixes, and Maintenance

Overview

Before taking the faucet apart, determine whether the leak comes from the spout, handle, base, or supply connection. The location provides a useful clue:

• Water drips from the spout when the faucet is off: a worn washer, valve seat, cartridge, or ceramic disc assembly may be allowing water through.
• Water appears around the handle: the cartridge, stem seal, O-ring, or retaining nut may need attention.
• Water collects around the faucet base: the base gasket or mounting hardware may be loose or deteriorated. Water can also be running down from the handle.
• Water leaks below the sink: inspect the supply lines, shutoff valves, hose connections, and faucet mounting connections.

Common faucet designs include compression faucets, ball faucets, cartridge faucets, and ceramic-disc faucets. A compression faucet typically has separate hot and cold handles that tighten down to stop the flow. A single-handle faucet may use a cartridge, ball, or disc mechanism. The exact replacement part must match the faucet model and mechanism, so keep the old component until the replacement has been confirmed.

Parts and tools checklist

• Adjustable wrench or appropriately sized open-end wrench
• Phillips and flat-head screwdrivers
• Hex key set, if the handle uses a set screw
• Slip-joint pliers or faucet-specific puller, if needed
• Replacement washer, O-ring, cartridge, valve stem, or faucet-specific repair kit
• Plumber’s silicone grease approved for faucet components
• Bucket, towels, and a flashlight
• Old toothbrush or soft brush for removing mineral deposits
• Painter’s tape or a small container for organizing screws

Checklist by scenario

For every faucet repair

1. Clear the cabinet or work area beneath the sink.
2. Place a bucket and towels under the connections.
3. Find the hot and cold shutoff valves under the sink. Turn both valves clockwise until they stop without forcing them.
4. Open the faucet to release remaining pressure, then close it.
5. Cover the drain or place a cloth over it so screws and clips cannot fall inside.
6. Take photographs before removing parts. These provide a useful reference during reassembly.
7. Arrange removed parts in order and label hot and cold components where applicable.

For a two-handle faucet that drips from the spout

1. Remove the decorative cap or handle screw, then lift off the handle.
2. Use a wrench to loosen the retaining nut or packing nut.
3. Remove the valve stem. On a compression faucet, inspect the rubber washer at the end of the stem.
4. Replace a flattened, cracked, or hardened washer with one of the same size and shape.
5. Inspect the valve seat inside the faucet body. If it is damaged or heavily pitted, a seat replacement or more extensive repair may be necessary.
6. Reinstall the stem, nut, and handle without overtightening. Test the faucet gradually.

For a single-handle cartridge faucet

1. Remove the handle’s cap or set screw and lift off the handle.
2. Remove the retaining clip, nut, or cover that holds the cartridge in place.
3. Note the cartridge orientation before pulling it out. If it is stuck, use a cartridge puller rather than excessive force.
4. Clean the inside of the valve body and remove loose mineral deposits.
5. Apply a thin layer of approved silicone grease to replacement O-rings if the manufacturer’s instructions allow it.
6. Insert the new cartridge in the same orientation, reinstall the retaining hardware, and refit the handle.
7. Open the shutoff valves slowly and check for leaks while moving the handle through its range.

For a loose faucet base or leaking supply connection

1. Dry the area completely so you can identify the source accurately.
2. From beneath the sink, check the mounting nuts or bracket holding the faucet. Tighten them carefully while keeping the faucet correctly aligned.
3. Check each supply connection and the flexible hose for moisture, splits, or corrosion.
4. Tighten a loose threaded connection slightly with a wrench. Do not use force on plastic nuts or bend the supply line.
5. If a hose or gasket is damaged, replace the complete affected part with a compatible component.
6. Dry everything again and test with a tissue or paper towel, which makes small leaks easier to see.

What to double-check

After reassembly, turn on the water slowly. Check beneath the sink first, then run the faucet at low and normal flow. Operate hot and cold handles separately if the faucet has two controls. Watch the spout, handle, base, supply connections, and shutoff valves for several minutes.

Confirm that the water drains normally and that no tool, screw, clip, or cleaning material has been left inside the cabinet. If the faucet has a removable aerator, unscrew it and rinse away debris that may have been disturbed during the repair. Reinstall it by hand and tighten only enough to prevent seepage.

If the faucet still drips, shut off the water again and reassess the diagnosis. A replacement washer will not correct a damaged valve seat, and a new cartridge will not fix a leaking supply hose. Check that the replacement part is the correct model, installed in the correct direction, and fully seated. Never compensate for a damaged part by forcing the handle tighter.

Common mistakes

• Skipping the shutoff step: Water pressure can turn a small repair into a flooded cabinet. Always close the local valves first and know where the main shutoff is located.
• Buying a part by appearance alone: Similar washers and cartridges may not be interchangeable. Use the faucet brand and model when available, or take the old part to a plumbing supplier.
• Overtightening connections: Excessive force can damage threads, gaskets, plastic nuts, and faucet bodies. Tighten gradually and test before tightening further.
• Mixing parts during disassembly: Keep hot and cold components separate and photograph the original arrangement.
• Using the wrong sealant: Do not apply sealant to every connection by default. Follow the fitting or faucet instructions; some connections seal with a gasket or compression ring.
• Ignoring corrosion or cabinet damage: A persistent leak beneath the sink can damage wood and flooring. Dry the area and inspect it after the repair.

Stop the repair and seek professional help if a shutoff valve will not close, a pipe or faucet body is cracked, water continues to flow after the supply is closed, a connection is badly corroded, or the leak is inside a wall or ceiling. A professional is also appropriate when access is restricted or the repair could affect multiple fixtures.

When to revisit

Use this checklist whenever a faucet begins dripping, a handle becomes difficult to operate, or moisture appears under the sink. Recheck the repaired area after the first use, later the same day, and again after several normal uses. This helps identify a slow leak that is not visible during a brief test.

Include faucet inspections in seasonal home-maintenance routines, especially before periods when the property will be vacant or when freezing conditions are possible. Look for stiff handles, mineral buildup, deteriorating hoses, loose mounting hardware, and damp cabinet surfaces. Clean the aerator when flow becomes uneven, wipe away deposits before they harden, and avoid using the handle as a support.

For a practical final checklist, confirm: the water is shut off before disassembly, the replacement part matches, connections are snug but not forced, the faucet is dry during testing, and no leak returns after repeated operation. If any item remains uncertain, leave the water off and arrange a professional inspection rather than allowing a small leak to become structural damage.