A Trusted, Code-Aligned DIY Repair Guide for Drips, Leaks, and Loose Handles

A leaky bathroom faucet wastes water, raises your water bill, and can even damage your countertop. The good news? Most bathroom faucet leaks are extremely easy to fix, even if you’ve never done plumbing work before.

This guide shows you exactly how to diagnose and repair a leaking faucet using methods consistent with IAPMO/UPC plumbing standards and manufacturer best practices. You’ll learn how to fix leaks from:

• A dripping faucet
• Leaks at the base
• Leaks from the handles
• Leaks under the sink (supply line or drain leaks)

And you’ll get recommended tools that work.

–

Tools & Materials You May Need

These are the exact tools plumbers use on bathroom faucets:

• Adjustable wrench
• Hex/Allen wrench set
• Phillips & flathead screwdriver
• Basin wrench (for tight under-sink spaces)
• Replacement cartridge (Moen, Delta, Kohler, Pfister, etc.)
• O-ring kit
• Plumber’s grease (lubricates O-rings and threads)
• Plumber’s tape (seals threaded pipe joints)
• Silicone caulk or plumber’s putty (seals flat, non-pressurized surfaces)
• Cup or towel for catching water

–

Before You Start: Identify Your Bathroom Faucet Type

Bathroom faucets come in three main styles:

1. Cartridge Faucet. Most modern faucets (Moen, Delta, Kohler).

Symptoms when leaking:
✔ Constant dripping
✔ Loose handle
✔ Water leaking from handle

2. Compression Faucet (older homes). Two handles, one for hot and one for cold.

Symptoms when leaking:
✔ Drip from spout even when closed
✔ Usually caused by a worn rubber washer

3. Ceramic Disc Faucet. Heavy, smooth handle movement.

Symptoms when leaking:
✔ Slow drips
✔ Handle becomes harder to move

If you’re unsure, search your model name (usually under the sink).

–

Step 1 — Turn Off the Water Supply

Look under the sink for two shutoff valves:

• Left = Hot
• Right = Cold

Turn each valve clockwise until fully closed.

If they won’t turn:
→ Use a wrench gently OR shut off the home’s main supply.

–

Step 2 — Plug the Drain

Faucet repairs involve tiny screws and O-rings.
Plug the drain with:

• The existing stopper, or
• A cloth, or
• Tape

This saves you from losing parts.

–

Step 3 — Remove the Faucet Handle

Most handles fall into two categories:

A. Screw on top or behind the handle

Use flathead or Phillips screwdriver.

B. Hidden screw under decorative cap

Pry up the cap using a small screwdriver and remove screw with Allen wrench.

Once the screw is out, lift the handle straight off.

–

Step 4 — Inspect and Remove the Cartridge (Most Common Fix)

Step 5 — Replace O-Rings and Lubricate Components

This is a required best practice for manufacturers and aligns with UPC maintenance standards.

Replace the following:

• O-rings
• Rubber seals
• Seat washers

Apply plumber’s silicone grease to all O-rings and moving parts.

This will stop leaks and extend faucet life.

–

Step 6 — Insert New Cartridge or Reinstall Old One

If replacing:

→ Use the exact model number
(You can usually find it stamped on the cartridge or under the sink.)

Insert cartridge:

• Align tabs
• Push straight down
• Tighten retaining nut
• Replace retaining clip
• Reinstall handle

–

Step 7 — Turn Water Back On & Test for Leaks

Turn valves counterclockwise slowly.

Check:

• Spout drip
• Handle leaks
• Base leaks
• Under-sink supply line leaks

If everything is dry, you’re done.

–

If the Faucet Leaks at the Base

This is almost always a failed O-ring on the faucet body.

Fix:

1. Remove handles
2. Remove faucet body
3. Replace O-ring
4. Grease it
5. Reinstall

–

If the Faucet Leaks From the Handles

Your handle stem or cartridge is worn.

Fix:

→ Replace the cartridge (single handle)
→ Replace seat washers (double handle)

–

If the Faucet Leaks Under the Sink

Common causes:

• Loose supply line nut
• Cracked supply line
• Improperly seated faucet
• Failed gasket

Fix:

1. Tighten supply line lightly with a wrench
2. Replace old supply lines (preferred for safety)
3. Reseal faucet gasket with silicone caulk or use plumber’s putty

–

Troubleshooting Chart: What’s Causing the Leak?

–

Replacement Parts for Fixing a Leaky Bathroom Faucet

Best universal tools:

• Adjustable wrench
• Basin wrench
• Non-hardening plumber’s grease

Replacement cartridges by brand:

• Moen 1224 / 1225 cartridges
• Delta single-handle cartridge RP50587
• Kohler ceramic valve kits
• Pfister 974-042 ceramic disc cartridge

–

People Also Ask

Why won’t my bathroom faucet stop dripping?

Because the internal cartridge or washer no longer forms a watertight seal.

Is it worth repairing a bathroom faucet?

Yes. Fixing a leak is cheaper than replacing the faucet and usually takes less than 20 minutes.

How much does a plumber charge to fix a faucet?

$125–$300 depending on brand and parts. Doing it yourself saves almost all of that.

How long do faucet cartridges last?

5–10 years depending on water quality and usage.

–

You’re Done!

Your bathroom faucet should now be leak-free and working like new.

–