How to Repair Faucet Leak, Step by Step

A faucet leak almost always comes down to one worn part inside the faucet, and most are an hour's work with a few basic tools. The repair has the same shape on every faucet: shut off the water, take the handle apart, replace the washer, O-ring, seal, or cartridge that wore out, then reassemble and test. This guide covers how to repair a faucet leak from the first drip to the final check, including how to tell which part failed.

Prefer to hand it off? Find a licensed plumber near you now for a fast quote.

How to Repair a Faucet Leak in 5 Steps (Quick Overview)

1. Shut off the water at the valves under the sink, then open the faucet to drain the line.
2. Plug the drain and remove the handle, usually held by a screw under a decorative cap.
3. Pull out the cartridge, stem, or worn washer and match it to a new part at the store.
4. Drop in the new part, grease the O-rings, and reassemble in reverse.
5. Turn the water back on slowly and run the faucet to confirm the drip is gone.

That is the whole job in miniature. The rest of this guide shows you how to find the leak, identify your faucet, and handle the parts that give people trouble.

What Causes a Faucet to Leak?

Most leaks trace back to a part that has lost its seal. Water pressure pushes against rubber and plastic components day and night until they wear down, harden, or pick up mineral grit and stop closing tight.

Worn Washers, O-Rings, Seals, and Cartridges

The most common cause of a dripping faucet is a worn rubber washer or O-ring. Compression faucets use a washer that presses against a valve seat every time you shut the tap. Cartridge, ball, and disc faucets rely on O-rings and internal seals instead. Once any of these flatten or crack, water sneaks past and drips from the spout. On cartridge faucets, the whole cartridge is often the failed part.

Corroded Valve Seat, Mineral Buildup, and Water Pressure

Sometimes the washer is fine and the surface it seals against, the valve seat, is pitted or corroded. Hard water leaves scale that chews up seats and clogs small openings. Very high water pressure can also force water past a seal that would otherwise hold. If a new part drips again fast, check the seat and your pressure next.

Diagnose Your Leak: Where Is the Water Coming From?

Before you touch a tool, find where the water shows up. The spot tells you which part is failing.

Match your symptom in the table, then jump to the matching fix below.

A drip from the spout that keeps going after you shut the handle is the classic worn-washer or worn-cartridge leak. Water around the handle points to failed stem or cartridge O-rings, which is where a search for how to repair faucet handle leak usually lands: the handle is wet, but the part is an O-ring underneath. Water under the sink is a connection problem, not an internal one, usually a loose supply line, a worn shutoff valve, or a drain joint. A line that splits open is a burst pipe under sink situation, so shut the main and call a 24/7 emergency plumber before the cabinet floods.

Identify Your Faucet Type

You cannot buy the right part until you know your faucet. There are four kinds, and you can usually tell them apart in about 30 seconds by how the handles move.

• Compression (two-handle). Separate hot and cold handles that you screw down tight to stop flow, getting firmer as they close. The oldest design and the only one with a rubber seat washer. Common on older bathroom and laundry sinks.
• Cartridge. One or two handles that move smoothly with no tightening feel. A single-handle version tilts up for volume and side to side for temperature. Inside is a replaceable cartridge. The most common style in newer homes.
• Ball. A single handle on a rounded cap that moves in all directions over a ball mechanism. Common on older kitchen sinks. It holds the most small parts, so a full repair kit is the smart buy.
• Ceramic disc. A single lever over a wide cylinder. Two ceramic discs slide to control flow. These rarely fail; when they do, it is usually the inlet seals or scale on the discs.

Tools and Parts You'll Need

• Adjustable wrench and slip-joint pliers
• Flathead and Phillips screwdrivers
• Allen (hex) key set for set screws
• Replacement washers, O-rings, seals, or a cartridge that matches your faucet
• Plumber's grease (silicone) and plumber's tape
• A rag, a small bowl, and a flashlight
• For compression faucets: a seat wrench and seat-dressing tool, plus white vinegar for descaling

Bring your old parts to the store. Faucet internals are not universal, and matching by sight beats guessing.

Step 1: Shut Off the Water and Prep the Workspace

Reach under the sink and turn both shutoff valves clockwise until they stop. If there are none, or they are stuck, shut off the main water valve for the house. Open the faucet to release pressure and drain the lines. Plug the drain so small screws and springs cannot fall in, then lay a towel in the basin to protect the finish and keep parts organized.

Step 2: Remove the Handle and Cartridge or Stem

Most handles hide their screw under a decorative cap on top or a set screw at the base. Pop the cap off with a flathead, or back out the set screw with an Allen key, then lift the handle straight up. Underneath is a retaining nut or clip. Loosen the nut with pliers or pull the clip, then withdraw the stem, cartridge, or ball assembly. Note the orientation as it comes out, since cartridges often have a flat side or notch that must line up later. Snap a photo first if you are unsure.

Step 3: Replace the Worn Part by Faucet Type

With the internal parts out, swap the one that failed.

Compression faucet (washer and valve seat). Unscrew the brass screw at the bottom of the stem and pop off the old seat washer. Fit a new washer of the exact same size and shape, then reinsert the screw. Run a finger inside the valve seat; if it feels rough or pitted, a new washer alone will not hold. Use a seat wrench to replace the seat, or a seat-dressing tool to smooth it. Replace the stem O-ring while you are there.

Cartridge faucet. Pull the old cartridge straight out, keeping track of which way it faces, and slide in a matching one in the same orientation. If the leak was around the base, replace the body O-rings and grease the new ones before sliding the spout back on. This is the standard fix for a single-handle kitchen or bathroom faucet that drips.

Ball faucet. Use a repair kit with springs, rubber seats, cam, and O-rings. Lift the old springs and seats out of the valve body with a screwdriver, drop in the new ones, then replace the ball, cam, and gasket. Grease the body O-rings before reseating the spout.

Ceramic disc faucet. Lift out the disc cylinder and clean or replace the neoprene inlet seals underneath. Soak the cylinder in white vinegar to clear scale, then set it back. Turn the water on gently the first time, since trapped air can crack a ceramic disc.

Clean or replace the aerator. A faucet that sprays sideways, dribbles after you shut it, or runs weak often has a clogged aerator, the screen at the spout tip. Unscrew it, rinse the grit, soak it in vinegar, and screw it back on. Replace it if the screen is torn. This solves a lot of "leaks" that are really just spray and dribble.

Step 4: Reassemble, Turn the Water On, and Test

Put everything back in reverse order, lining up cartridges and stems the way they came out. Hand-tighten the retaining nuts, then snug them with pliers without overdoing it, since overtightening cracks parts and causes the next leak. Reattach the handle and screw. Open the faucet handle so air can escape, then turn the shutoff valves back on slowly, a quarter turn at a time. Let the faucet run clear, shut it off, and watch the spout and base for a full minute. No drip means you are done.

Still Leaking After the Repair? Troubleshooting

A repair that still drips usually points to one of these:

• Wrong-size or pinched part. An O-ring or washer a hair too big, or seated crooked, will leak. Recheck the size against the old one.
• Damaged valve seat. On compression faucets, a pitted seat lets water past a brand-new washer. Resurface or replace it.
• Overtightened assembly. Cranking the retaining nut can deform a cartridge or seal. Back it off and re-snug gently.
• Mineral buildup. Grit on the seat or discs holds the seal open. Clean every surface before reassembly.
• High water pressure. A drip that only shows at night may be a pressure spike; a pressure check and a regulator fix the root cause.

If you have replaced the part, cleaned the seat, and it still leaks, the body itself may be worn out and the faucet is due for replacement.

Bathroom, Kitchen, Tub, and Outdoor Faucets

The four types cover the mechanics, but where the faucet lives changes a few details.

• Bathroom sinks. Often two-handle compression or a single cartridge. A how to repair bathroom faucet leak job is usually the quickest of the bunch.
• Kitchen faucets. Tall spouts mean larger spout O-rings, and pull-down models add a spray hose to watch. A how to repair kitchen faucet leak fix often comes down to those base O-rings, not the cartridge.
• Tub and shower faucets. To repair a tub faucet leak or a bathtub faucet leak, you work with a cartridge or compression stem set behind the wall, reached through the handle. A valve leaking behind tile is harder to reach, so it is a good time to get a plumber to fix the shower. For a worn valve, diverter, or leaking showerhead, see our guide to shower repair.
• Outdoor spigots. A how to repair hose bib leak fix is usually a new packing washer under the handle nut or a fresh stem washer. After a hard winter, a spigot that leaks may have a split body from a frozen line and needs replacing.

DIY vs. Plumber: What a Faucet Leak Repair Costs

Doing it yourself, the only cost is the part and maybe a tool you do not own yet. Washers and O-rings are among the cheapest parts in any hardware store, and even a cartridge or full ball-faucet kit is a small spend. The trade is your time and a trip to the store.

A plumber costs more, but you pay for speed, the right parts on the truck, and an eye that spots a worn seat or a faucet not worth saving. What you pay depends on your faucet type and brand, whether parts are still made, how easy the faucet is to reach, local labor rates, and whether it is an after-hours visit. As a rule of thumb, if a basic part swap does not stop the drip, or the faucet is old and corroded, paying for professional faucet repair often beats buying parts twice.

How Much Water a Dripping Faucet Wastes

A slow drip looks harmless and adds up fast. To measure your own waste, set a measuring cup under the drip, time how long it takes to fill, then multiply across a day. That water lands on your bill whether you use it or not, and a hot-water drip costs more since you pay to heat what runs down the drain. Fixing the leak fast is the cheapest water-saving move in the house.

When to Call a Professional Plumber

Plenty of faucet leaks are a 20-minute job. Some are not. Call a pro when:

• The shutoff valves are seized or missing and you would have to kill the whole house supply.
• Parts for your faucet are discontinued and you cannot match them.
• The valve seat or faucet body is corroded, or hard-water damage will not clean off.
• The leak is behind tile, inside a tub valve, or anywhere you would open drywall.
• You find a steady stream or a burst pipe under sink instead of a drip. That is a water-damage risk, and a 24/7 emergency plumber is the right call.

A good plumber will also tell you when a faucet is too far gone to save. To skip the diagnosis, find a licensed plumber near you and have it handled the same day.

How to Prevent Future Faucet Leaks

• Do not crank the handles shut. Firm is enough; extra muscle wears washers out early.
• Descale aerators and cartridges a couple of times a year if you have hard water.
• Add a little plumber's grease to O-rings whenever the faucet is open.
• Have high water pressure checked and add a regulator if needed, since high pressure shortens the life of every seal in the house.
• Treat very hard water at the source so scale stops building up in fixtures.

Frequently Asked Questions

What is the most common cause of a leaky faucet? A worn rubber washer or O-ring is the usual culprit. These parts lose their seal over time, so water slips past and drips from the spout. On single-handle faucets, a failed cartridge is the most common cause.

Why does my faucet drip when the water is off? Water is getting past the part meant to block it: a worn seat washer or pitted valve seat on a compression faucet, or a failed cartridge or O-ring on a cartridge faucet. Replacing that part stops the drip.

Is it worth repairing a faucet? Usually yes, since parts are cheap and the fix is quick. Replacement makes more sense when the faucet body is corroded, parts are no longer made, or you have repaired it several times.

Repairing a faucet leak is one of the most satisfying small fixes in a home: a few dollars in parts and a quiet sink again. If the drip outlasts your patience, or a part swap will not hold, call a licensed local plumber now for a fast quote and get it handled today.