By Caleb MorganUpdated November 2026
To repair a leaking faucet in the bathroom, you shut off the water, take the handle and stem assembly apart, identify the worn part, replace it and reassemble the faucet. Most drips come from a worn washer, O-ring or cartridge, and the job usually takes under an hour with basic tools. The steps below cover the most common single-handle and two-handle designs.
Identify the Type of Leak Before You Start
Start by figuring out what kind of faucet you have, because the fix depends on the mechanism inside. Two-handle compression faucets use rubber washers on brass stems and tend to drip from the spout when the handle is closed. Single-handle faucets usually use a cartridge, and a steady drip or a leak around the base of the handle often points to that cartridge or a worn O-ring. Check where the water is coming from before you take anything apart.
Shut Off the Water and Disassemble the Faucet
Close the supply valves under the sink, then open the faucet to drain any remaining water. Cover the drain with a towel so a dropped screw doesn’t disappear. Pop off the decorative handle cap, remove the handle screw, and lift the handle off. Unscrew the packing nut or retaining clip, then pull out the stem or cartridge.
- Turn off both supply valves under the sink.
- Open the faucet to relieve pressure and drain the lines.
- Remove the handle cap and handle screw.
- Take out the packing nut, retaining clip or cartridge clip.
- Pull out the stem or cartridge and keep parts in order.
Replace the Worn Parts
Compression Faucets: Washers and Seats
Unscrew the brass stem and check the rubber washer at its base. If it is flattened, cracked or pitted, replace it with an identical size. Inspect the valve seat inside the faucet body as well. If it is rough, a seat wrench can smooth it, and you should match the seat size exactly.
Cartridge Faucets: Cartridge and O-Rings
If the faucet uses a cartridge, the cartridge itself is usually the part to replace. Many manufacturers, including Delta and Moen, sell replacements matched to specific models, so bring the old cartridge to the store or check the brand name and model number on the body. Lubricate new O-rings with plumber’s grease before installing them. Replace any O-rings on the faucet body at the same time.
Reassemble and Test the Faucet
Reverse the disassembly steps, keeping parts in the order you removed them. Hand-tighten the packing nut or clip first, then snug it gently with a wrench so you don’t crack the plastic or brass. Reattach the handle, then slowly open the supply valves. Run the faucet at low and high settings and check for drips at the spout and around the base. Tighten the packing nut slightly if you see seepage, but do not overtighten.
Common Mistakes
- Forgetting to shut off the supply valves, which leads to a wet cabinet floor.
- Buying a washer or cartridge that doesn’t match the brand and model.
- Overtightening the packing nut, which can crack the handle or stem.
- Skipping the valve seat check, so a new washer still leaks.
- Mixing up stem parts, which can make the faucet hard to turn or cause it to leak.
Recommended Gear
A basic adjustable wrench and a set of Allen wrenches cover most bathroom faucet handles, and a seat wrench helps with compression valves. Plumber’s grease keeps new O-rings and washers sealed and turning smoothly. Replacement cartridges and washer kits matched to your brand are worth having on hand before you start.
For more model-specific help, see Bathroom Sink Faucet Repair Kit: 7 Best Picks Compared (2026) and Bathroom Moen Faucet Repair: Lever Handle Kit Review (2026). If your leak is at the tub, Repair Tub Faucet Drip: A Step-by-Step Guide to Stop Leaks (2026) covers that setup. For a Delta sink, Delta Faucet Repair Kits: How to Choose and Use the Right One explains how to match parts to the model.
FAQ
Why does my bathroom faucet still drip after I replace the washer?
The valve seat is often the cause. If it is scratched or corroded, a new washer will not seal properly, so inspect and smooth the seat or replace it.
Do I need to replace the whole faucet to stop a leak?
Usually not. Most leaks come from inexpensive, replaceable parts like washers, O-rings and cartridges.
When should I call a professional?
If the faucet is corroded beyond repair, the supply lines leak, or you can’t identify the parts, a licensed plumber can diagnose the problem safely.
Conclusion
Shutting off the water, identifying your faucet type and replacing the worn washer, O-ring or cartridge will stop most bathroom faucet leaks. Take your time with reassembly and test slowly before you walk away. If the leak returns, check the valve seat and confirm your replacement parts match your model.
Related reading
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About Caleb Morgan
Caleb Morgan is part of our editorial team and reviews and edits our kitchen faucets & sinks guides, checking product details against manufacturer specifications and owner feedback.
