Kohler A112 18.1 Faucet Parts: How to Identify and Replace Them

By Caleb Morgan

Updated November 2026

Kohler A112 18.1 faucet parts are the components that make a Kohler faucet carrying the A112.18.1 plumbing standard work, from the cartridge and valve body to the spout, handle and aerator. This guide shows you how to identify the part you need, confirm it fits your faucet, and replace it without buying the wrong piece. The short version: match the faucet model and the internal mechanism first, then order the part.

Identify Your Faucet Before You Order Anything

The A112.18.1 designation refers to a performance standard for plumbing fixtures, so it tells you the faucet meets a specification but not which parts fit it. Kohler has used many different valve designs under that umbrella, so a part that looks identical can have a different stem length, cartridge height or spline count. Start by locating the model number, which is usually stamped on the underside of the spout, on the escutcheon plate or on a label under the sink. Write it down exactly, including any suffix letters.

Shopping for one? See our guide: 6 Best Kohler Bath Faucet Repair Kits and Parts Compared (2026).

Next, decide what kind of part you need. A dripping faucet almost always points to the cartridge or valve seat, while low flow usually means a clogged aerator or a worn cartridge. If you are unsure, the Kohler parts diagram for your specific model is the most reliable reference. For a broader overview of kitchen components, see Kohler Kitchen Faucet Parts: How to Identify and Replace the Right Ones.

Common Kohler Replacement Parts and How to Match Them

Most repairs involve one of four components. Each has its own matching method.

• Cartridge: Measure the height from the bottom of the cartridge to the top of the stem, and count the splines or tabs on the stem. Kohler uses several cartridge styles, so the number of splines and the cap design both matter.
• Valve seat and seat wrench: Check the thread size and the seat shape. Many leaks blamed on the cartridge are actually caused by a pitted seat.
• Aerator: Note the thread size (commonly M22 or 15/16-inch male) and whether the aerator is a flow-restricting insert. Using the wrong aerator changes spray pattern and pressure.
• Handle and escutcheon: Handles are often sold separately from the cartridge, so confirm the set screw position and handle style before buying.

Compare the old part side by side with the new one before you install it. If the stem, height or thread differs even slightly, return it and check the model number again.

Step-by-Step Replacement Process

Work on a clean sink area with a towel laid in the basin so small parts cannot fall down the drain.

1. Shut off the hot and cold supply valves under the sink, then open the faucet to relieve pressure.
2. Remove the handle by loosening the set screw, usually hidden under a decorative cap, then lift it off.
3. Remove the retaining nut or cap that holds the cartridge, and pull the cartridge straight out with pliers or the Kohler-specified puller.
4. Clean the valve body and seat of mineral deposits using a soft brush and white vinegar.
5. Insert the new cartridge with the index tab aligned to the body, reinstall the retaining nut and handle, then turn the supply valves back on slowly.

Run the faucet on hot and cold for a minute to clear air and debris, then test for leaks at the base and the spout.

Recommended Gear

• Silicone plumber’s grease: Lubricates O-rings so cartridges slide in without tearing seals. View on Amazon
• Faucet cartridge puller: Removes stuck cartridges without damaging the valve body. View on Amazon
• Adjustable basin wrench: Reaches the mounting nuts under the sink where a standard wrench cannot. View on Amazon

Common Mistakes and Tips

• Ordering by faucet name alone. Two faucets with the same finish can use different cartridges.
• Forcing a stuck cartridge. Use a puller rather than twisting it, which can crack the body.
• Skipping the valve seat inspection when a new cartridge still drips.
• Overtightening the retaining nut, which can warp the seal and cause new leaks.
• Reusing old O-rings. Replace them whenever you open the valve body.

For more troubleshooting on leaks and pressure, see Leaky Kitchen Faucet Moen Fixes: 7 Best Parts and Kits Compared for comparable repair approaches, and Kohler Tub Faucet With Diverter: Step-by-Step Repair and Replacement Guide if your fixture is in the bathroom.

FAQ

Where is the Kohler model number on my faucet?

It is usually stamped on the underside of the spout, on the escutcheon plate or on a label under the sink. Record it with any suffix letters before ordering parts.

Can I use a cartridge from another brand?

Sometimes, but cartridge dimensions and spline counts vary between manufacturers. Compare stem height and spline count carefully, and when in doubt, buy the Kohler-specified part.

Should I consult a professional for a repair?

If the shutoff valves are corroded or leak when you open them, or if a supply line bursts, stop and call a licensed plumber to avoid water damage.

Conclusion

Identifying your exact Kohler model is the key step, because the A112.18.1 standard alone does not tell you which cartridge, seat or aerator fits. Measure, match and compare the old part before you order. With the right component and a careful install, most Kohler faucet repairs take under an hour.

About Caleb Morgan

Caleb Morgan is part of our editorial team and reviews and edits our kitchen faucets & sinks guides, checking product details against manufacturer specifications and owner feedback.