If you’re searching for how to fix a sink faucet from leaking, the short answer is: identify the faucet type, shut off the water supply, and replace the worn internal parts—usually a cartridge, washer, or O-ring. A dripping faucet can waste up to 3,000 gallons of water per year, according to the U.S. Environmental Protection Agency WaterSense program, which also notes that fixing leaks can save homeowners about 10% on water bills. Most basic repairs take 30–60 minutes with common tools, and the parts cost between $5 and $30 at any hardware store. However, if the leak persists after replacing standard components, you may be dealing with a corroded valve seat or a deeper supply-line issue that requires professional help.
Why Sink Faucets Leak: Root Causes and Warning Signs
Before you start disassembling anything, understand that a leak is rarely a random event. It’s the result of normal wear on rubber or plastic parts, mineral buildup from hard water, or improper installation. The most common culprits include:
- Worn washers – Standard compression faucets use rubber washers that flatten and crack over time.
- Failed O-rings – These small rings seal the spout base and handle; they dry out and split.
- Corroded cartridge or valve seat – In cartridge and ball-type faucets, mineral deposits can pit the metal surfaces.
- Loose packing nut – A simple tightening issue that causes leaks around the handle.
- High water pressure – Excessive pressure (above 80 psi) accelerates wear on all seals.
You’ll also notice specific symptoms: water dripping from the spout even when the handle is off (worn internal seal), water pooling around the handle base (loose O-ring or packing nut), or a hissing sound when the faucet is closed (pressure issue). If you see water stains or rust on the faucet body, that’s a sign of a slow internal leak that has been ignored.
Tools and Materials You Will Need
Gather these items before you begin. Most are inexpensive and reusable.
- Adjustable wrench or pliers (for nuts and fittings)
- Phillips and flathead screwdrivers
- Allen wrench (for set screws on handles)
- Bucket and old towels
- Plumber’s tape (Teflon tape)
- Replacement parts (washer, O-ring, cartridge, or ball assembly – specific to your faucet brand)
- White vinegar or a commercial descaling solution (for mineral buildup)
- Safety glasses and work gloves
If you don’t know your faucet brand, look for a logo on the base or under the handle. Many manufacturers stamp the name on the underside of the spout. You can also remove the handle to find a model number.
Step-by-Step Instructions to Fix Your Leaking Sink Faucet
Step 1: Turn Off the Water Supply
Locate the shut-off valves under the sink—there should be one for hot and one for cold. Turn both clockwise until they stop. If you don’t have fixture shut-offs, turn off the main water valve for your house. Open the faucet handle to release any remaining pressure and let the water drain into a bucket. Leave the handle in the open position while you work.
Step 2: Identify Your Faucet Type
There are four main types of sink faucets in US homes. Each requires a different repair approach:
| Faucet Type | Common Leak Point | Repair Method | Parts Needed |
|---|---|---|---|
| Compression (two handles) | Worn washer at the valve seat | Remove handle, replace washer, reseat | Washers, O-rings |
| Ball (single handle, rotating ball) | Worn ball assembly or springs | Replace ball and springs | Ball assembly, springs, seals |
| Cartridge (single handle, pull-out) | Faulty cartridge | Pull cartridge, replace with new | Cartridge, O-rings |
| Ceramic disc (single handle, modern) | Cracked disc or seals | Replace disc module or cartridge | Disc cartridge |
If you’re unsure, remove the handle and look inside. A cartridge looks like a cylindrical metal or plastic plug; a ball faucet has a rounded cap with a rotating ball underneath; a compression faucet has a hexagonal brass stem.
Step 3: Disassemble the Faucet Handle
Use a screwdriver to remove the small screw on the handle. On some models, the screw is hidden under a decorative cap—pop it off with a flathead screwdriver. For single-handle faucets, loosen the set screw with an Allen wrench. Once the screw is out, wiggle the handle upward and off the stem. If it’s stuck, use a puller tool or gently tap it with a rubber mallet.
Step 4: Remove the Internal Assembly
Depending on your faucet type:
- Compression faucet: Use a wrench to unscrew the packing nut, then lift out the stem. You’ll see a rubber washer at the bottom—pry it out with a screwdriver.
- Ball faucet: Unscrew the cap and pull out the ball, springs, and rubber seals. Note their order.
- Cartridge faucet: Remove the retaining clip or nut, then pull the cartridge straight up with pliers. Twist gently if it’s stuck.
- Ceramic disc: Remove the screw holding the disc module and lift it out.
Inspect the parts you removed. Look for cracks, flattened rubber, or mineral crust. If you see white or greenish deposits, soak the parts in vinegar for 30 minutes to dissolve scale.
Step 5: Replace Worn Parts
Take the old parts to a hardware store to match exact replacements. For washers, choose the correct size (flat or beveled). For cartridges, note the brand and model—many stores have a cross-reference guide. Always replace all O-rings in the assembly, even if only one looks worn, because they age at the same rate.
Step 6: Clean the Valve Seat and Reassemble
Use a valve seat wrench or a piece of fine sandpaper to smooth any rough spots on the metal seat where the washer presses. Wipe away debris. Apply a thin layer of plumber’s grease to new O-rings and washers to help them slide and seal. Reinstall the parts in reverse order. Tighten nuts firmly, but don’t over-tighten—you can strip threads or crack plastic parts.
Step 7: Turn the Water Back On and Test
Close the faucet handle, then slowly open the shut-off valves. Turn the faucet on and off several times to check for drips. Inspect under the handle and around the spout base for any moisture. Let it run for a minute to ensure the pressure is stable. If you still see a leak, the issue may be deeper in the supply lines or the faucet body itself.
When to Call a Professional Plumber
While many faucet repairs are DIY-friendly, certain situations warrant professional help. If you encounter any of the following, stop and call a licensed plumber:
- The faucet body is cracked or corroded—replacement may be necessary.
- You find significant rust or scaling inside the supply lines.
- Water pressure is consistently high or low, indicating a broader plumbing issue.
- The leak persists after replacing all standard parts—this could be a hidden leak behind the wall.
- You’re uncomfortable working with tools or don’t have the right equipment.
Attempting a complex repair without experience can cause water damage, which is far more expensive than a service call. For example, a burst supply line can leak 100 gallons per hour, leading to mold and structural damage. The CDC’s Healthy Water site highlights that moisture from leaks can promote mold growth, which is a health risk for your family.
Preventive Maintenance to Extend Faucet Life
After you fix the leak, take these steps to prevent future problems:
- Install a water pressure regulator if your home’s pressure exceeds 80 psi (check with a gauge).
- Clean faucet aerators every 3–6 months to remove sediment.
- Replace washers and O-rings every 2–3 years as a preventative measure.
- Consider upgrading to a WaterSense-labeled faucet, which uses 30% less water without sacrificing performance, per the EPA’s WaterSense program.
- If you have hard water, install a whole-house water softener to reduce mineral buildup.
Frequently Asked Questions
Q: How much does it cost to fix a leaking sink faucet if I hire a plumber?
A: In the US, a typical service call ranges from $100 to $250 for labor, plus the cost of parts (usually $10–$40). Prices vary by region and the complexity of the repair. If the faucet needs replacement, expect $200–$500 total for a basic model installed.
Q: Can I fix a leaking faucet without turning off the water?
A: No. You must shut off the water supply to avoid flooding and injury. Always close the shut-off valves under the sink or the main valve. If you skip this step, you’ll have water spraying everywhere and you won’t be able to see the parts clearly.
Q: Why does my faucet leak even after I replaced the washer?
A: If the leak persists, the valve seat may be corroded or pitted. You can smooth it with a valve seat wrench, or if it’s severely damaged, you may need to replace the entire faucet. Another possibility is that you installed the wrong size washer or didn’t tighten the packing nut enough.
Q: Is a dripping faucet really a big deal?
A: Yes. According to the EPA, a faucet leaking one drip per second wastes over 3,000 gallons per year—that’s enough for 180 showers. It also increases your water bill and can stain your sink with mineral deposits.
Q: What’s the difference between a washer and an O-ring?
A: A washer is a flat, disc-shaped seal that presses against a valve seat to stop water flow. An O-ring is a round rubber ring that seals moving parts, like the handle or spout base. Both wear out, but they serve different functions.
Q: How do I know if my faucet needs a new cartridge or just a cleaning?
A: If you see mineral buildup on the cartridge, try cleaning it with vinegar first. If the leak stops, you’re done. If it still drips, replace the cartridge. Cartridges are inexpensive and readily available for most brands.
Final Thoughts and Next Steps
Fixing a leaking sink faucet is a manageable DIY task for most homeowners, saving you money and conserving water. However, if you run into unexpected complications—like a cracked valve or a hidden wall leak—don’t hesitate to call a professional. For reliable assistance with any plumbing issue, including leak detection, pipe repair, or sump pump services, our team is here to help. We also handle drain cleaning, toilet repair, water heater repair, and sewer line repair. For a limited time, new customers can save on their first service—claim your exclusive offer today. Remember, a small drip today can become a major flood tomorrow. Take action now to protect your home and your wallet.
Byline: MyTownPlumber Editorial Team