Why Is Water Leaking From Under My Kitchen Faucet? 4 Common Causes and How to Fix Them
You notice a puddle forming around the base of your kitchen faucet—this problem might seem small, but it can lead to water damage, mold, and costly repairs if you ignore it.
The good news is that a leak from under your faucet is usually caused by a few common, easy-to-fix problems. By understanding where the water is coming from, you can often fix it yourself without calling a plumber.
TL;DR
- A leak at the faucet base usually means worn-out O-rings or a failing cartridge—these internal parts break down from regular use and heat exposure .
- If the leak only happens while the water is running, dirt or debris on the seals is likely preventing a proper seal .
- If the leak continues after you turn the faucet off, the valve or cartridge is worn out and needs replacing .
- Sometimes a handle leak can drip down and pool at the base, making it look like the base is the problem .
- A loose mounting nut or connection can also cause water to escape from the base area .
The Real Causes Behind a Leak Under the Faucet
Water leaking from under your kitchen faucet usually points to one of these common issues.
Worn-Out O-Rings or Seals
This is the most common reason for a leak at the faucet base . Inside your faucet, small rubber rings called O-rings create watertight seals. Over time, they wear down from regular use, heat, and water exposure . When these rings fail, water escapes through the base or around the spout .
Signs it could be this: Water pools around the base only when the faucet is running. This usually means dirt or debris on the seals prevents a watertight seal .
A Failing Cartridge or Valve
The cartridge controls water flow. If it cracks or wears out, it can allow water to escape in places it should not . Dirt and debris can also collect in the valve, preventing it from properly controlling water flow .
Signs it could be this: The leak continues even after you turn the faucet off. This is a classic sign of a worn-out cartridge or valve .
Loose Connections or a Check Valve Issue
Sometimes the problem is mechanical rather than from worn parts. A loose mounting nut or packing nut can allow water to escape at the base . Some faucets also have a small hole called a “weep hole” at the back—if the spacer or check valve assembly wears out, water can leak from here .
Signs it could be this: The leak appears to come from a specific point near the base or handle connection .
A Handle Leak Misdiagnosed as a Base Leak
Water can also trickle down from the handle and pool at the base, making it look like the base is leaking . This is a helpful distinction because a handle leak has a different fix.
How to test: Wrap a paper towel around the handle and turn on the faucet. If the towel gets wet, the leak is coming from the handle, not the base .
Comparison Table: Base Leak Causes and Fixes
| Symptom | Likely Cause | What to Fix |
|---|---|---|
| Water pools at the base when running | Worn or dirty O-rings and seals | Replace the seal kit |
| Leak continues after faucet is off | Worn-out cartridge or valve | Replace the cartridge/valve |
| Leak from a small hole behind the faucet | Worn-out check valve/spacer | Replace the spacer/check valve |
| Water runs down from the handle area | Handle leak dripping down | Fix the handle leak first |
Step-by-Step Fix Guide
Here is a simple approach to fixing the leak, starting with the easiest steps.
Step 1: Identify Where the Water Is Really Coming From
- Wrap a paper towel around the handle and turn on the faucet. If the towel gets wet, the leak starts at the handle .
- If the base is wet but the handle is dry, the leak is likely at the base.
Step 2: Turn Off the Water Supply
- Safety reminder: Always turn off the water supply before working on plumbing. Locate the shut-off valves under the sink and turn them off . If you cannot find them, turn off the main water supply for your home .
Step 3: Remove the Faucet Handle
This step gives you access to the internal parts.
- Remove the decorative cap and the screw underneath .
- If the handle is stuck, loosen the set screw more .
- The bonnet (decorative covering beneath the handle) twists off counterclockwise .
Step 4: Inspect and Replace the O-Rings
- Remove the spout by pulling straight up . You will see the faucet body with grooves containing O-rings .
- Replace the old O-rings with new ones .
- Pro tip: Lubricate the new O-rings with silicone-based lubricant before reassembling . This helps create a proper seal. Do not use petroleum-based grease, as it can damage rubber seals .
Step 5: Inspect and Replace the Cartridge
If O-ring replacement does not stop the leak, the cartridge is likely the problem .
- Remove the cartridge from the faucet body .
- Take it to a hardware store to match the correct replacement .
- Install the new cartridge and reassemble the faucet.
Step 6: Reassemble and Test
- Put everything back together in the reverse order .
- Turn the water supply back on and run the faucet. Check the base for any leaks.
“Most kitchen problems come from small maintenance habits that are often ignored. A regular check for drips under the sink is an easy habit that can save you thousands of dollars in water damage.”
When to Call a Professional
Some problems need a professional plumber.
- If replacing the O-rings and cartridge does not stop the leak, the problem may be a cracked valve body or a deeper issue .
- If you are not comfortable working with plumbing components .
- If the faucet is under warranty, the manufacturer may send free replacement parts .
Frequently Asked Questions (FAQ)
Why is my kitchen faucet leaking at the base?
The most common reason is worn-out O-rings or a failing cartridge inside the faucet body . The seals break down over time and allow water to escape.
How do I fix a leak under my kitchen faucet handle?
First, turn off the water supply. Then, remove the handle and bonnet, replace the worn O-rings or cartridge, and reassemble .
Why does my faucet leak only when the water is running?
This usually means dirt or debris has collected on the O-rings, preventing them from sealing when water flows . The fix is to clean or replace the seals .
Why does my faucet keep leaking even after I turn it off?
This is a sign of a worn-out cartridge or valve . It cannot fully shut off the water flow, so water continues to drip .
Can I use plumber’s grease on O-rings?
No, you should use silicone-based lubricant. Petroleum-based grease can damage rubber seals and cause problems with the faucet’s movement .
A leak under your kitchen faucet is usually a straightforward fix that you can handle yourself. By identifying whether the leak is from the handle or base, and then replacing the worn O-rings or cartridge, you can stop the drip and protect your kitchen.
Which kitchen problem do you want solved next? Share your thoughts in the comments.
Learn more about kitchen faucet maintenance and repairs from trusted sources:
