Most people find this leak by accident. They reach for the dish soap and the cabinet floor is damp, or there's a musty smell that wasn't there last month. By then the particleboard has usually started to swell.
Stop the water first
- Clear everything out of the cabinet so you can see and reach.
- Turn the two shutoff valves clockwise until they stop. That isolates this faucet.
- If there are no valves, or they won't turn, shut off the main water valve for the house.
- Dry everything with a towel and leave the doors open.
Find where it's coming from
Dry every surface, then put a folded paper towel under each connection and run the faucet for a minute. The towel that gets wet first tells you the source.
| Where the water shows up | Likely source |
|---|---|
| On the supply line, running down from the faucet | The faucet's own connection or the mounting seal above |
| At the shutoff valve itself | A worn valve packing or a failing valve |
| At the braided line's nut | A loose or worn supply line connection |
| Only when the sprayer is used | The pull-down hose or its quick-connect |
| Only when the sink drains | The drain or trap, not the faucet |
That last row matters. Drain leaks and faucet leaks look the same on a cabinet floor but are different repairs.
The common fixes
Supply lines
Braided lines don't last forever. The rubber core inside can fail with no warning. If yours are old, it makes sense to replace both while everything is apart.
Shutoff valves
Older valves can drip from the stem once they're turned after years of sitting. Replacing them means shutting off the main line, and it's worth doing, because a working shutoff makes every future repair easier.
The faucet's mounting seal
If water runs down the faucet's shanks from above, the leak is really on top: the seal between the faucet and the sink has failed, and water is getting in around the base. That's covered in leaking faucet repair.
Pull-down hose
Kitchen sprayer hoses flex every time you use them, and they crack near the fittings. See kitchen faucet problems.
Dealing with the damage
Once the leak is stopped, dry the cabinet properly. A fan pointed into the open cabinet for a day or two helps. If the floor is soft or swollen, or if you see mold, mention it when you call. It changes what needs to happen and in what order.
When to call instead of trying it yourself
Call if the shutoff valves won't turn, if the leak continues after tightening a fitting, if you can't tell where the water is coming from, or if the cabinet floor is already damaged. Overtightening a compression fitting is one of the easiest ways to turn a drip into a spray.