If your Kohler faucet is dripping from the spout, the fix depends on which valve type is inside. Kohler faucets use two main internal mechanisms: traditional cartridges with rubber seals, and ceramic disc cartridges. Knowing which one you have tells a licensed plumber exactly what to order before they arrive.
The Two Valve Types Kohler Uses
Traditional cartridges (sometimes called rubber cartridges) contain rubber O-rings and seats that compress to stop water flow. When the rubber wears out or cracks, water gets past even with the handle fully off, and you get a steady drip from the spout.
Ceramic disc cartridges use two hardened ceramic discs that rotate against each other to control flow. They’re the more common type in Kohler’s faucets made in recent decades, including many single-handle kitchen and bathroom faucets. The ceramic is very durable, but mineral deposits or a cracked disc will eventually allow water through.
Both fail the same way from your perspective: water drips from the spout with the handle fully closed. The repair is different for each.
Why the Faucet Is Dripping
Traditional cartridge failure usually comes from age and use. The rubber O-rings and seats inside flatten or crack over time. Hard water accelerates this.
Ceramic disc fouling happens when calcium and mineral scale builds up on the disc surface, preventing the discs from seating flush. A cracked disc is less common but does happen. Ceramic discs can also develop micro-fractures from debris or wear over time.
Less common causes include a damaged valve seat inside the faucet body (more relevant on older Kohler faucets) or a loose packing nut. A plumber will rule those out quickly.
How a Plumber Diagnoses It
The first thing a plumber does is shut off the supply stops under the sink and confirm the drip stops. That confirms the leak is the valve, not a loose connection downstream.
Then they pull the handle and trim to expose the cartridge. On many Kohler single-handle faucets, the handle is held by a set screw under a decorative cap. Once the cartridge is out, they can see it directly:
- A traditional cartridge will show visible wear or cracked rubber seals.
- A ceramic disc cartridge will have visible mineral buildup on the disc faces, or a visible crack.
A good plumber brings common Kohler cartridges on the truck. If your faucet is a less common model, they may need to order the part.
What the Repair Involves
Traditional cartridge replacement: The plumber removes the old cartridge, notes the orientation (critical on single-handle faucets, because installing it backward reverses hot and cold), puts in the new one, and reassembles. Straightforward when the part is on hand.
Ceramic disc service: If the discs are fouled with mineral scale, a plumber may clean them and reinstall. If a disc is cracked, the whole cartridge assembly gets replaced. Kohler makes replacement disc cartridges for most of their faucet lines.
Either way, the plumber turns the supply back on slowly and checks for leaks at the valve body and packing before closing everything up.
What’s Safe to Look at Yourself
You can identify which faucet line you have. Look for the Kohler logo and any collection name stamped on the faucet body or in the original paperwork. Kohler’s website has a parts finder where you can look up diagrams by collection name. Knowing your specific Kohler faucet line helps the plumber confirm which cartridge to bring.
You can also turn off the supply stops under the sink before the plumber arrives, which saves a bit of time.
When to Call a Licensed Plumber
For a dripping Kohler faucet, a licensed plumber is the right call. The repair itself isn’t complicated, but it requires the correct replacement part for your specific faucet, and getting the cartridge orientation wrong creates a new problem.
If you’re in California, verify your plumber’s license at cslb.ca.gov before work starts. A valid C-36 plumbing license is what you’re looking for. It takes about 30 seconds to check.
Tell the plumber upfront whether you have hard water in your area. That affects both what they look for and how they advise you on preventing the next failure.