Likely cause: debris or wear in the cartridge

Why this happens

Kohler's guidance for a leak at the base of the spout says dirt and debris collect in the valve or cartridge. Kohler adds that a continuous leak usually means debris or wear in the valve or cartridge, while a leak that stops on its own is often debris sitting on a seal. On some Kohler models a check valve or spacer under the valve is part of the repair; Kohler names its Check Valve Service Kit 1042007 as one example, and other part numbers depend on the model.

How to fix it

1. Shut off both stops under the sink and open the faucet to release pressure. Close the drain.
2. Remove the handle and the retaining nut or clip, then pull the cartridge straight up. Note which way it faced.
3. Wipe grit off the cartridge gaskets with a damp cloth and rinse the valve body. Pfister suggests this cleaning step before you buy parts.
4. Reinstall, reopen the stops slowly, and check the base after ten minutes with the faucet off.
5. If it still leaks, replace the cartridge. Match it by brand and model number, or compare length and stem shape against the identification index linked below.

When to stop. If the cartridge will not come out with hand pressure and a puller, stop before you crack the faucet body.

The part that fixes it

Pick the cartridge that matches your valve, not your faucet's finish. The 35 mm, 40 mm and 47 mm ceramic cartridges fit the brands listed on each.

Not sure which part you have? Pull the old one and match it by brand, length and broach on Stems & Cartridges, an identification index of faucet stems and cartridges by part number.

Start this troubleshooter over

Vent, Valve & Volt is published by the team behind FourHome. Browse all FourHome replacement faucet and shower parts on the FourHome Amazon store.