A bathroom sink faucet drips primarily because of a worn internal cartridge, a degraded rubber washer, a loose O-ring, or a damaged valve seat; the specific failing part depends on whether you have a cartridge, compression, ball, or ceramic disc faucet.
A slow drip from your bathroom faucet is more than a nighttime annoyance—that steady *plink* wastes gallons of water a month and drives up your utility bill. The good news is that you can fix most drips yourself in under an hour with a basic toolkit and a trip to the hardware store. This guide walks you through diagnosing the exact culprit by faucet type and then gives you the step-by-step repair process that actually stops the leak.
What Faucet Type Do You Have? (The Diagnosis Starts Here)
Every bathroom faucet falls into one of four categories, and each has a different set of common failure points. Look under the handle and at how the faucet moves to identify yours before buying any replacement parts.
| Faucet Type | Visual Clue | Most Likely Cause of Drip |
|---|---|---|
| Cartridge | Single handle that moves up/down and left/right, or two separate handles on a single base | Failed cartridge—the plastic or brass core that mixes hot and cold water |
| Compression | Two separate handles (hot and cold) that twist to open and close | Worn rubber washer or gasket at the end of the stem |
| Ball | Single handle with a rounded dome shape at the base | Worn O-rings, springs, or a damaged ball mechanism |
| Ceramic Disc | Single handle that operates smoothly with very little effort | Worn disc cartridge or debris trapped between the ceramic discs |
How To Identify Which Side Is Leaking (Dual-Handle Faucets)
If your faucet has two handles and one side is dripping, isolate the leak by turning off only that side’s shut-off valve under the sink. Turn the handle valves clockwise until they stop. If the drip stops, you’ve found the failing assembly. If the drip continues, the problem is on the other side. Stuck shut-off valves? Turn off the main water supply for the house and replace both valves while you’re at it.
The Step-By-Step Repair Process That Works
The following procedure applies to all standard residential bathroom faucets. The only difference is which internal part you extract and replace.
1. Shut Off The Water And Drain The Lines
Locate the hot and cold shut-off valves under the sink. Turn them clockwise (righty-tighty) until they won’t go further. If your sink has no shut-off valves or they’re frozen, turn off the main water supply to your whole house. Then open the faucet handle to release any trapped water pressure—a dry faucet is a safe faucet to work on.
2. Protect The Sink And Faucet Finish
Plug the drain with a stopper or lay a towel over it. A dropped screw or spring disappearing into the drainpipe will turn a 20-minute job into a plumbing extraction project. Wrap masking tape around any chrome or brushed-nickel surfaces your wrench will contact, because scratched metal cannot be un-scratched.
3. Remove The Handle
Pop off the decorative cap on top of the handle with a small flathead screwdriver. Under it you’ll find a screw—usually Phillips or Allen (hex). Remove the screw and pull the handle straight up and off the stem. If it sticks, wiggle gently rather than prying, which can crack the handle.
4. Access The Internal Assembly
Once the handle is off, you’ll see a retaining ring, nut, or clip holding the internal mechanism in place. Loosen it with a wrench or pliers. For cartridge faucets, pull the old cartridge straight out. For compression faucets, unscrew the packing nut and lift out the stem assembly. For ball faucets, remove the retaining clip and lift out the ball and cam assembly. For ceramic disc faucets, the disc cartridge lifts out after you remove the retaining screws.
5. Replace The Worn Part
Take the old part to the hardware store to match it exactly. Cartridges look similar and a slightly different one will still drip. Install the new washer, O-ring, spring, or cartridge into the same position. Lubricate new rubber seals with a dab of plumber’s grease or petroleum jelly—skipping this step causes friction that ruins the new part prematurely.
6. Reassemble And Test
Put everything back in reverse order. Tighten the packing nut or retaining ring snug, but do not crank it—overtightening cracks plastic housings and deforms rubber seals. Turn the water valves back on slowly (counterclockwise). Run the faucet for five minutes without the aerator to flush any debris that might have gotten into the lines during repair. Then screw the aerator back on and check for drips.
How To Fix A Leak At The Base Of The Faucet
If water drips from where the faucet body meets the countertop, the problem isn’t the internal cartridge—it’s the gasket or O-ring that seals the base. Pour a cup of water over the top of the faucet where it meets the sink. If water appears underneath, the base gasket is compromised. Unscrew the mounting nut under the sink, lift the faucet off, clean the surface, and apply a fresh ring of plumber’s putty before reseating the faucet.
Common Mistakes That Keep The Drip Going
- Not plugging the drain. One dropped part and you’re fishing through a P-trap. Use the towel or stopper.
- Overtightening. Snug is the target. Too tight cracks stems, deforms washers, and causes the same drip you were trying to fix.
- Ignoring the aerator. A clogged aerator restricts flow and creates backpressure that can make a faucet behave oddly. Soak it in white vinegar to dissolve mineral deposits.
- Incorrect reassembly. Washers and gaskets are directional. If the new part has a beveled edge, that edge faces the water stream.
- Skipping lubrication. Plumber’s grease keeps O-rings from rolling or tearing during installation. O-rings installed dry will fail within weeks.
When To Call A Plumber
If you’ve replaced the cartridge, washers, and O-rings and the faucet still drips, the valve seat inside the faucet body may be corroded. Resurfacing a valve seat requires a specialized tool (a seat-dressing kit) that most homeowners don’t own. At that point, consider whether a new faucet is more cost-effective than chasing old parts on an aging fixture. Cartridges alone can cost $25–$50, and a decent new bathroom faucet starts around $60. Our curated roundup of the best bathroom sink faucets can help you pick a reliable replacement that won’t drip for years.
Checklist: The Real Fix In Four Steps
- Identify your faucet type (cartridge, compression, ball, or ceramic disc) using the table above.
- Shut off the water, protect the sink, and remove the handle to access the internal assembly.
- Replace the worn part—cartridge for modern single-handle faucets, washers for two-handle compression models, O-rings for ball faucets.
- Lubricate new seals, reassemble, flush the lines, and check for drips.
FAQs
Can I fix a dripping faucet without turning off the water?
No. Opening any faucet component under full water pressure will flood the cabinet and waste more water than the drip itself. Always turn off the shut-off valves or main supply before removing any part.
How much water does one drip per minute waste in a month?
A faucet dripping once per second wastes about 3,000 gallons per year—roughly the water used to run 150 loads of laundry. Even a slow drip adds up to noticeable monthly cost on most water bills.
Will tightening the handle stop a drip permanently?
No. Tightening a handle temporarily crushes a worn washer or cartridge into the seat, but the damaged rubber will soon loosen again. The permanent fix is replacement of the worn part, not compression of the old one.
Why does my faucet drip only at certain times of day?
A drip that appears or worsens at specific hours is usually connected to water pressure fluctuations. Municipal water pressure increases during off-peak hours (late night), and higher pressure can force past a partially worn washer or O-ring that holds fine at lower pressure.
Is a leaky faucet covered by home insurance?
Damage caused by a sudden burst pipe is often covered, but a slow, ongoing drip that causes damage is generally considered a maintenance issue and is not covered by standard homeowners insurance.
References & Sources
- Moen. “Bathroom Faucet: Dripping From The Spout.” Official manufacturer guide identifying cartridges as the primary cause of spout drips.
- Portland.gov. “How to fix a faucet leak.” Official municipal water-efficiency guide with detailed step-by-step repair instructions.
- The Home Depot. “6 Steps to Fix a Leaky Faucet.” General repair guide covering washers, O-rings, and valve seats across faucet types.
- HOROW. “How to Fix a Leaky Faucet.” Step-by-step guide covering all faucet types and lubrication steps.