How to Identify and Fix a Leaky Faucet

Why a Leaky Faucet Demands Immediate Attention

A faucet that drips once per second can waste more than 3,000 gallons of water per year—enough to fill a small swimming pool. According to the U.S. Environmental Protection Agency, household leaks in the United States waste nearly 1 trillion gallons annually, with leaky faucets being one of the most common culprits. Beyond the environmental toll, that steady drip adds to your water bill, often by $50 to $100 or more annually. Fixing the problem not only saves money but also prevents water damage to countertops, cabinets, and floors. Most leaky faucet repairs are straightforward and require only basic tools—no calling a plumber required.

Identifying the Source of the Leak

Before you pick up a wrench, determine exactly where the water is escaping. Leaks typically occur at one of four locations: the handle, the spout, the base of the faucet, or the water supply lines underneath the sink. Each location points to different internal problems and repair strategies.

Leaks at the Faucet Handle

If water drips from around the handle when the faucet is turned on—or even when it’s off—the issue is most likely a worn O-ring or a loose packing nut. For compression faucets, a deteriorating stem washer can also cause handle leaks. Turn off the water supply, then remove the handle to inspect the O-ring; if it’s cracked, flattened, or feels brittle, replace it and apply fresh plumber’s grease.

Leaks at the Spout

A stream of water flowing from the spout even when the handle is fully closed usually points to a failed cartridge (in cartridge faucets) or a worn rubber washer (in compression faucets). In ceramic disc faucets, a spout leak often indicates a scratched or chipped disc. You’ll need to disassemble the faucet to inspect and replace these components.

Leaks at the Base of the Faucet

Water pooling around the base—where the faucet meets the sink—typically means the base gasket or the mounting O-ring has failed. Over time, mineral deposits, hard water, and simple aging can degrade these seals. Fixing this usually requires removing the entire faucet body, so it’s a slightly more involved repair. Check for a loose base too; a rock-solid base is less likely to leak.

Leaks from the Water Supply Lines

Not all faucet leaks actually come from the faucet itself. Supply lines—the flexible hoses connecting the faucet to the shut-off valves—can develop pinhole leaks, cracks, or loose connections. Use a flashlight to inspect the underside of the sink. If you see moisture or corrosion on the supply line or at the connection nut, tighten the nut or replace the line. Modern braided stainless steel supply lines are more durable than rubber ones and are a good upgrade.

Common Causes of Faucet Leaks

Understanding why faucets leak helps you diagnose the problem faster and prevents unnecessary disassembly. The root cause almost always falls into one of these categories.

Worn out washers: In compression faucets, a rubber washer at the end of the valve stem presses against the seat when the handle is closed. Over years of use, that washer compresses, splits, or hardens, allowing water to seep past. This is the most common cause of a dripping spout in older faucets.
Damaged O-rings: These small rubber rings seal the stem where it passes through the faucet body. A damaged O-ring usually causes a leak around the handle or base. They’re cheap to buy but require disassembly to replace.
Corroded valve seats: The valve seat is the metal disc or surface against which the washer (or cartridge) seals. If it becomes pitted or corroded from hard water, the mating seal will leak no matter how new the washer is. You can sometimes clean the seat, but severe corrosion means you need a seat replacement or a whole new faucet.
Loose or broken parts: A loose packing nut, a cracked handle, or a worn retaining clip can allow movement that breaks the seal. Vibrations from water hammer or frequent use can also loosen parts over time. Regular inspection and tightening can prevent leaks.
Faulty cartridges: Most modern faucets use a cartridge that controls both hot and cold water. Inside the cartridge, small O-rings, seals, or ceramic discs can fail. If you have a single-handle faucet that drips, the cartridge is the first thing to check. Cartridges are specific to each model, so keep your faucet’s model number handy.
Mineral buildup: Hard water deposits can accumulate on valve seats, O-rings, and inside cartridges, causing them to stick, wear prematurely, or fail to seal. Periodic cleaning with white vinegar or a descaler can extend the life of your faucet.

Tools and Materials You’ll Need

Most faucet repairs require only a handful of tools. Assemble these before you start to avoid a frustrating trip to the hardware store mid-project.

Adjustable wrench – for loosening and tightening nuts under the sink. A basin wrench is also handy for reaching awkward nut positions.
Screwdrivers – both flathead and Phillips. Some faucet handles use hex set screws, so a small hex key set is also recommended.
Replacement washers, O-rings, and cartridges – buy the specific size or model needed for your faucet. Universal kits exist, but exact matches seal better.
Plumber’s grease – silicone-based grease designed for faucet seals. It lubricates O-rings and washers during reassembly, preventing premature drying and cracking. Never use petroleum jelly or oil-based products.
Bucket or towel – to catch any water left in the lines after you shut off the supply. A small plastic container or a rag works well.
Flashlight – essential for inspecting the underside of the sink and seeing into dark faucet cavities.
Thread seal tape (plumber’s tape) – useful for resealing threaded connections on supply lines or spout connections.
Paper towels and vinegar – for cleaning mineral deposits from valve seats and other metal surfaces before reassembly.

Step-by-Step Fix: By Faucet Type

The repair procedure varies depending on whether your faucet is a compression, cartridge, ceramic disc, or ball-type design. Identify your faucet type by looking at its handle mechanism and style. If you don’t know the brand, remove the handle to see the internal parts—or look up the model on the manufacturer’s website.

Fixing a Compression Faucet (Two-Handle Style)

Compression faucets are the oldest type, typically found in older homes. They have separate hot and cold handles that you turn multiple rotations to open or close. The leak usually comes from a worn stem washer.

Turn off the water supply under the sink. Open the faucet to drain remaining water.
Use a screwdriver to remove the decorative cap on the handle, then the handle screw. Pull the handle straight off.
Using an adjustable wrench, unscrew the packing nut that secures the valve stem. Slide it up the stem.
Pull the stem out of the faucet body. At the bottom of the stem you’ll see a brass screw holding a black rubber washer. Remove the screw and the worn washer.
Take the old washer to the hardware store to match size and shape exactly. Flat washers are common, but some faucets use beveled or tapered shapes.
Before installing the new washer, clean the valve seat (the metal surface inside the faucet where the washer seals) with a small wire brush or vinegar-soaked rag. If the seat is pitted, use a valve seat reamer or replace the seat.
Attach the new washer with the brass screw, ensuring it faces the correct direction. Apply a thin layer of plumber’s grease to the stem and O-ring.
Reassemble in reverse order: slide the stem back in, tighten the packing nut (snug but not over-tightened), replace the handle and cap, and turn the water on. Check for leaks.

Fixing a Cartridge Faucet (Single or Two-Handle)

Cartridge faucets are common in modern homes. They use a sealed plastic or brass cartridge that contains all the moving parts. A leaky spout usually means the cartridge needs replacement.

Shut off the water supply and drain the faucet.
Remove the handle. On some models a small set screw is hidden under a decorative button or cap. On others, the handle is held by a Phillips screw on top.
Depending on the design, you may need to unscrew a retaining nut or clip that holds the cartridge in place. Use an adjustable wrench or channel locks carefully.
Pull the cartridge straight upward. If it’s stuck (common with hard water buildup), use a cartridge puller tool or gently wiggle it free. Do not use excessive force that could damage the faucet body.
Take the old cartridge to a plumbing supply store or check the manufacturer’s model number for an exact replacement. Cartridges are brand-specific, so generic ones rarely fit.
Before inserting the new cartridge, clean the faucet body with a cloth and apply a light coat of plumber’s grease to the O-rings on the new cartridge.
Press the new cartridge into place, ensuring alignment tabs line up with slots in the body. Reinstall the retaining nut and handle.
Turn on the water and test. If the leak persists, double-check that the cartridge is fully seated and that the O-rings are not pinched.

Fixing a Ceramic Disc Faucet

Ceramic disc faucets are the most durable type, using two polished ceramic discs that slide against each other to control water flow. Leaks usually occur from scratches, chips, or mineral deposits on the discs.

Shut off water supply and drain.
Remove the handle and any decorative escutcheon. For many modern pull-down or pull-out kitchen faucets, this may require unscrewing a base ring after removing the handle.
Lift the cartridge or disc assembly out of the faucet body. It often consists of two ceramic discs sandwiched together inside a plastic housing.
Inspect the surface of the ceramic discs for scratches, chips, or white mineral crust. Small deposits can sometimes be cleaned with white vinegar and a soft cloth. Severe damage requires replacing the entire cartridge.
If the cartridge is replaceable, obtain an exact match. Some ceramic disc faucets allow you to replace only the discs, but most require a full cartridge swap.
Apply plumber’s grease to the O-rings and carefully reassemble. Make sure no debris gets between the discs.
Test for leaks. If the spout still drips after cleaning or replacement, the valve seat inside the faucet body may be damaged, requiring professional help or a new faucet.

Fixing a Ball-Type Faucet (Kitchen Style)

Ball faucets are common in kitchens and share a single handle that moves a metal ball to control temperature and flow. They have several springs and seals that can wear out.

Shut off water and drain.
Remove the handle and the dome cap that covers the ball. You’ll need a specialized tool (often a plastic key or hex wrench) to loosen the cam.
Lift out the ball and inspect the springs, rubber seals, and seat. These small components often disintegrate or flatten over time.
Replace all springs, seats, and seals with a universal ball faucet repair kit. The kits are inexpensive and widely available.
Apply plumber’s grease to the new seals and reassemble in reverse order. Tighten the cam just enough to hold the ball; over-tightening will make the handle stiff and cause wear.
Turn the water back on and check for leaks at the spout and handle base.

Preventive Maintenance Tips

Regular upkeep can significantly extend your faucet’s life and reduce the chance of leaks. Follow these simple practices every few months:

Clean the aerator: Mineral deposits and debris can clog the aerator screen, causing reduced flow and backpressure that stresses internal seals. Unscrew the aerator (the tip of the spout) and soak it in white vinegar overnight, then scrub with a toothbrush. Reinstall carefully.
Lubricate O-rings and seals: Every year or two, remove the handle, clean the stem, and apply a small amount of silicone plumber’s grease to the O-rings. This prevents them from drying out and cracking.
Check supply lines: Look under the sink for any signs of moisture, corrosion, or bulging on flexible hoses. Replace rubber supply lines with braided stainless steel for better durability.
Avoid over-tightening: When turning off the faucet, use gentle but firm pressure. Cranking the handle down hard compresses washers and O-rings prematurely, leading to leaks.
Install a water softener or conditioner: Hard water accelerates mineral buildup and corrosion. If your area has hard water (over 7 grains per gallon), consider a whole-house water softener. At the least, clean your faucet internals with a descaling solution annually.
Replace washers and O-rings proactively: If you notice handle stiffness, a squeak, or a very slight drip, don’t wait. Replacing a $0.50 O-ring now can save you from a $150 plumber call later.

When to Call a Professional Plumber

While the repairs described above are DIY-friendly for many homeowners, some situations warrant expert help. Do not hesitate to call a licensed plumber if:

You can’t stop the leak after replacing seals and cartridges: Persistent leaks may indicate a cracked faucet body or a corroded valve seat deep inside the faucet. Replacing the entire faucet is often more cost-effective than continued repairs, and a plumber can do it safely.
Water damage or mold is present: If the leak has been active for a while, you may find softened drywall, rotting cabinet wood, or visible mold. A plumber can identify hidden damage and a general contractor may be needed for repairs.
Multiple fixtures are leaking at once: This could indicate a broader issue such as high water pressure, water hammer, or a failing pressure regulator. A professional can test your system and install a pressure-reducing valve if necessary.
You have a complex faucet design: Some modern pull-down, touch-activated, or sensor faucets have intricate electronic components and proprietary cartridges. Attempting a DIY fix could void the warranty or cause more damage. Consult the manufacturer or hire a plumber experienced with that brand.
You’re uncomfortable with plumbing work: If you have limited experience or few tools, or if the shut-off valves under the sink are stuck or leaking, it’s safer to call a professional. A small mistake—like cross-threading a supply line—can cause a flood.

Conclusion: Save Water, Save Money, Protect Your Home

A leaky faucet might seem like a minor annoyance, but ignoring it wastes water, money, and can lead to costly water damage. By learning to identify the source and fixing the issue yourself with new washers, O-rings, or cartridges, you gain confidence in home maintenance and extend the life of your fixtures. Always start with the simplest solutions—check the handle, spout, and supply lines—and work your way to more complex internal repairs. And remember: regular preventive maintenance, including cleaning the aerator and lubricating parts, will keep your faucet running drip-free for years. The tools cost little, the parts are cheap, and the water you save makes a real difference for your wallet and the environment.

For more water-saving tips and detailed instructions, visit the EPA WaterSense Fix a Leak Week resources and check out The Family Handyman guide to faucet repair. If you need a new faucet, look for the WaterSense label to ensure efficiency and durability.