1 Overview
A dripping faucet is one of the most common plumbing annoyances in a home, and it is also one of the most fixable. That steady drip may seem harmless, but over time it wastes water, stains the sink basin, and can raise your water bill. More importantly, the drip is usually a signal that a small internal part has worn out. Because the repair typically involves only a few basic tools and a replacement part, many homeowners can handle it themselves in under an hour.
This guide is written for everyday homeowners who want to understand what is happening inside a faucet and how to stop the drip. It covers the most frequent causes, from a worn washer or O-ring to a corroded valve seat or a loose cartridge. You do not need to be a plumber to follow along, but you do need to work carefully and respect the limits of your comfort and skill. If at any point you feel unsure, especially when dealing with shutoff valves that will not close or fittings that will not budge, stop and call a licensed professional.
Before you begin, gather a few basic tools: an adjustable wrench, a screwdriver set, a flashlight, and a towel or small bucket. You may also need replacement parts, which you can match to your faucet by checking the manufacturer's manual or taking the old part with you to a hardware store. The goal is not to rebuild the entire faucet, but to identify the single worn component that is allowing water to escape and replace it correctly.
2 How it works
Most household faucets work on a simple principle: a handle moves an internal mechanism that opens or closes a passage for water. In a traditional compression faucet, turning the handle presses a rubber washer against a metal seat to stop the flow. In a cartridge or ceramic-disc faucet, the handle rotates or lifts a cartridge that aligns or blocks ports inside the valve body. In a ball-type faucet, a rotating ball with openings controls the mix of hot and cold water. Each design has its own wear points, but they all rely on a tight seal to keep water from escaping when the faucet is closed.
When the faucet is off, water pressure pushes against that seal. If the seal is perfect, no water passes. If the seal is worn, cracked, or misaligned, a small amount of water slips past and exits through the spout as a drip. The drip may be steady or intermittent, and it may change with temperature because some materials expand and contract. That is why a faucet sometimes drips more after hot water has been running.
The three most common failure points are the washer or O-ring, the valve seat, and the cartridge. A washer or O-ring is a soft rubber or plastic part that creates the actual seal. A valve seat is the metal surface the washer presses against; over time, minerals in water can corrode or pit that surface. A cartridge is a larger assembly that moves inside the faucet body; it can loosen, crack, or collect debris. Understanding which type of faucet you have and which part is failing is the key to a successful repair.
3 Signs something is wrong
The most obvious sign is a drip from the spout when the faucet is fully closed. You may notice it as a slow bead of water that forms every few seconds, or as a thin stream that never quite stops. Sometimes the drip is worse when the handle is in a particular position, which can point to a worn cartridge or a loose handle. If the drip stops when you press down or wiggle the handle, the problem is likely in the moving parts rather than the water supply.
Another sign is water appearing around the base of the faucet rather than from the spout. This can mean an O-ring or seal under the handle has failed, allowing water to escape before it reaches the spout. You might see mineral buildup, white crust, or greenish staining around the base, which suggests a slow leak has been present for a while. A puddle under the sink cabinet can also indicate a loose connection or a failing valve, though that is a different problem from a spout drip.
You may also notice changes in water pressure or temperature control. A faucet that drips and also runs slowly may have debris in the cartridge or aerator. A handle that feels loose, grinds, or spins without resistance often points to a worn cartridge or a stripped stem. Finally, a drip that appears only after you use hot water can indicate that heat is expanding a worn part and opening a small gap. Any of these signs is a good reason to investigate before the problem worsens.
4 Likely causes
The first and most common cause is a worn washer or O-ring. These small rubber or plastic parts are designed to compress and seal, but they harden, crack, or flatten over time. Once they lose their flexibility, water slips past them even when the handle is closed. In compression faucets, the washer sits at the bottom of the stem and presses against the valve seat. In other designs, O-rings seal the cartridge or handle area. Replacing a worn washer or O-ring is usually inexpensive and straightforward.
The second common cause is a corroded or pitted valve seat. The valve seat is the metal surface that the washer contacts. Minerals in water, especially in hard-water areas, can build up or eat into that surface. A rough or uneven seat prevents the washer from sealing completely, so even a new washer may not stop the drip. In some faucets the seat can be removed and replaced; in others it must be resurfaced or the entire valve body replaced. If you replace a washer and the drip continues, inspect the seat carefully with a flashlight.
The third common cause is a loose or worn cartridge. Cartridge faucets rely on a single assembly to control both flow and temperature. If the cartridge is not seated properly, or if its internal seals are worn, water can bypass the closed position. A loose retaining nut or a handle that has worked loose can also allow the cartridge to shift. Sometimes simply reseating or tightening the cartridge solves the problem, but if the cartridge is cracked or heavily worn, it should be replaced with a matching part from the manufacturer.
5 Step-by-step diagnosis and fix
First, shut off the water supply to the faucet. Look under the sink for the shutoff valves and turn them clockwise until they stop. If there are no local valves, turn off the main water supply to the house. Open the faucet handle to release any remaining pressure and let the water drain. Place a towel or bucket under the work area to catch drips. If you are unsure how to shut off the water safely, call a licensed plumber before proceeding.
Second, identify your faucet type. Check the manufacturer's manual or look for a name or diagram under the handle. Compression faucets usually have separate hot and cold handles and a stem with a washer. Cartridge faucets typically have a single handle or a lever. Knowing the type tells you which parts to expect and how to disassemble the faucet without damaging it.
Third, disassemble the faucet carefully. Remove the handle by prying off the decorative cap and unscrewing the retaining screw. Take a photo at each stage so you can reassemble correctly. Use an adjustable wrench to loosen the packing nut or retaining nut, then pull out the stem or cartridge. If it resists, do not force it; a gentle twist or a specialized puller may be needed. Inspect the washer, O-rings, and seat for cracks, flattening, or mineral buildup.
Fourth, replace the worn parts. Match the new washer, O-ring, or cartridge to the old one exactly, using the manufacturer's recommended part or a matching replacement. If the valve seat is corroded, replace it if possible or consult the manufacturer's instructions for resurfacing. Clean any debris or mineral deposits from the valve body with a soft cloth or mild vinegar solution, then rinse and dry.
Fifth, reassemble the faucet in reverse order. Tighten the retaining nut snugly, but do not overtighten, as this can crack the cartridge or strip threads. Reattach the handle and test the faucet by turning the water supply back on slowly. Watch for leaks at the base and spout. If the drip persists, turn off the water again and recheck the alignment of the cartridge or the condition of the seat. If you cannot stop the leak after a careful attempt, or if you find damaged threads or a cracked valve body, call a licensed professional.
6 Safety and when to call a professional
Safety always comes first with any plumbing repair. Before you touch any part of the faucet, disconnect the water supply by closing the shutoff valves or the main valve. Open the faucet to relieve pressure, and never work on a faucet while water is still pressurized. If your home has a water heater, be aware that hot water can scald; let the system cool if you have been running hot water. Keep a towel and bucket handy to prevent slippery floors, and work in a well-lit area so you can see small parts clearly.
Electrical safety matters too. If a faucet is near an electrical outlet or appliance, do not allow water to spray or drip onto electrical components. If you see exposed wiring or a damaged outlet near the sink, stop and call a licensed electrician. For any work involving gas lines, always turn off the gas and call a licensed professional; this guide does not cover gas appliances. If you are unsure about any step, or if the shutoff valve will not close, do not proceed. A stuck valve can break and cause a flood, which is far more expensive than hiring help.
Call a licensed plumber if you cannot identify the faucet type, if the valve seat is badly corroded, if the faucet body is cracked, or if the shutoff valves are damaged or will not turn. Also call a professional if you have tried replacing the obvious parts and the drip continues, or if you discover water damage under the sink. A professional can diagnose hidden issues, replace difficult components, and ensure the repair meets local plumbing codes. Knowing when to stop is a sign of good judgment, not failure.
7 Frequently asked questions
Q: Can I fix a dripping faucet without turning off the water? A: No. You must shut off the water supply before disassembling any faucet. Even a small amount of pressure can cause water to spray when you remove a part, and you risk damaging the internal components. Close the local shutoff valves or the main water valve, then open the faucet to drain remaining water. If you cannot find or close the shutoff valve, call a licensed plumber.
Q: How do I know which part to replace? A: Start by identifying your faucet type and inspecting the internal parts. A worn washer or O-ring usually looks flattened, cracked, or brittle. A corroded valve seat looks rough, pitted, or covered in mineral deposits. A loose cartridge may wiggle, feel gritty, or show cracks. If you are unsure, take the old part to a hardware store and match it, or check the manufacturer's manual for the correct replacement part number. Replacing the wrong part will not stop the drip.
Q: What if the drip continues after I replace the parts? A: If the drip persists, turn off the water again and recheck your work. The cartridge may not be seated correctly, the retaining nut may be too loose or too tight, or the valve seat may still be damaged. Clean any debris from the valve body and inspect the new parts for damage. If the faucet body itself is cracked or the seat cannot be repaired, the faucet may need to be replaced. At that point, or if you are uncomfortable continuing, call a licensed professional to diagnose and complete the repair safely.