Faucet leaking at the base or under the handle

Water around the base of a single-handle faucet usually comes from worn o-rings, a cartridge passing water, or a handle leak that runs down and puddles on the base plate. A paper towel and a few minutes of watching will tell you which.

Also searched as: faucet leaking at base, kitchen faucet leaking at base of spout, single handle faucet leaking under sink, bathroom faucet leaking from base when turned on.

A brass faucet stem, a plastic cartridge, seats and springs and an Allen key laid out on a workbench

Every question and answer on this page, in order

Question 1: Where do you see the water?

Dry the faucet, the counter and the cabinet floor with a towel, run the faucet for a minute, then look.

On the counter, around the base of the faucet: go to question 2
Under the sink, inside the cabinet: Likely cause: a supply line or connection under the sink

Question 2: Wrap a dry paper towel around the handle and run the faucet. Is the towel wet?

Moen notes that a handle leak can run down and puddle on the base plate, so it looks like a base leak when it is not.

Yes, the towel is wet: Likely cause: a loose retainer ring under the handle
No, the towel stays dry: go to question 3

Question 3: Does water show up at the base only while the faucet runs, or also when it is off?

Dry the base, leave the faucet off for ten minutes, and check again.

Only while it runs: go to question 4
Also when it is off: Likely cause: debris or wear in the cartridge

Question 4: Does the faucet have a pull-out or pull-down spray head?

A pull-out or pull-down head comes off the spout on a hose. A side sprayer that sits in its own hole in the sink does not count here.

Yes, pull-out or pull-down: Likely cause: the hose connection or the cartridge in a pull-down faucet
No, a standard spout (with or without a side sprayer): Likely cause: worn spout o-rings

Possible results

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