How to Identify a Faucet Cartridge by Diameter, Stem and Rotation

If you need to identify faucet cartridge hardware from a leaky faucet, start by measuring the old part rather than trying to match it by appearance. For practical faucet cartridge identification, the details that matter most are body diameter, overall height, stem shape, spline count if present, rotation, base geometry and any visible markings.

A cartridge that looks almost identical in a picture can still be the wrong part.

Start With the Faucet

Before removing anything, take a clear picture of the faucet and handle. Record the brand and model number if you can find them, and note whether the faucet is single-handle or two-handle.

On a two-handle bathroom or kitchen faucet, also note whether you are working on the hot or cold side.

If low flow is the only problem, check the restriction first. SANIKB’s kitchen faucet low water pressure guide walks through the aerator, shutoff valves, water supply lines and hose before moving to the cartridge.

Once the water supply is shut off, remove the handle cap and screw. Depending on the faucet, the cartridge may be held by a retaining nut, bonnet nut or clip. Keep the nut, cap, screw and other small parts together so reassembly is easier.

For a general look at faucet disassembly, see This Old House’s leaky faucet repair guide.

Measure the Cartridge Body

Start with the main cartridge body, not the locating tabs sticking out from the bottom.

Record:

• body diameter
• body height
• overall height
• exposed stem height

For overall height, measure from the bottom of the cartridge base to the top of the stem.

A caliper is ideal, especially when two parts are only a few millimeters apart. If you are sending pictures by email or taking the old cartridge to a hardware store, include one picture with a ruler or caliper beside it.

Diameter is useful, but it is only the first filter. Two cartridges with the same diameter may still use different stems or bases.

Look Closely at the Stem

The stem is where the handle connects.

Check the shape from both the top and the side. It may be round, square, D-shaped, flat-sided, keyed or splined.

If it has splines, count them. Also measure the stem diameter and how far it extends above the cartridge body.

If there are no splines, record the actual profile instead. A D-shaped stem, for example, should not be treated as interchangeable with a round one simply because the cartridge body is the same size.

This is one reason replacement cartridges that look similar can behave very differently once the handle goes back on.

For another visual reference, iFixit has a useful ceramic cartridge identification guide.

Check Rotation on Two-Handle Faucets

This is easy to overlook.

If the faucet has separate hot and cold handles, record which side the cartridge came from and which way the handle turns to open.

Hot- and cold-side valves may use opposite rotation even when the cartridges look nearly identical.

Write down clockwise or counterclockwise before you remove the old part. That small detail can save you from ordering a replacement that fits physically but operates the wrong way.

For a single-handle mixer, do not use the same hot-side/cold-side logic. Confirm the cartridge orientation against the faucet model.

Turn the Cartridge Over

The bottom of the cartridge often tells you more than the top.

Compare:

• locating pins
• alignment tabs
• slots or keyways
• inlet and outlet openings
• seals
• base shape

If any of these are different, the cartridge may not seat correctly even when the diameter and height match.

Take a picture from the bottom before you shop. A top photo alone is rarely enough for an unknown part.

Check for Numbers or Other Identifying Marks

Look over the body, stem area and base for a molded logo, stamped number, letters or other identifying marks.

Photograph them before scrubbing the old cartridge too aggressively. Faint molded numbers can actually become harder to read after cleaning.

If the faucet has a recognizable brand such as Moen, Delta or Pfister, combine the brand with the visible number when you search.

If there is no usable number, that does not end the search. Measurements, stem shape, rotation and base geometry can still narrow the replacement down considerably.

Confirm the Part Against the Faucet Model

Measurements help you narrow the options. The faucet model should make the final call whenever model-specific parts information is available.

Check the parts diagram, installation sheet or supplier record and compare it with the cartridge you removed.

Pay particular attention to:

• stem profile
• rotation
• locating features
• inlet layout
• retaining method

Do not purchase replacement parts from a single product picture. If two cartridges look close, compare the dimensions and bottom view before you decide which one is the right part.

Faucet Cartridge Identification Checklist

For maintenance teams, it is worth saving this information with the faucet SKU and installation location. The next leaky faucet is much easier to deal with when the correct replacement is already documented.

What to Send SANIKB for Cartridge Confirmation

For a SANIKB faucet, send:

• faucet model or SKU
• one picture of the full faucet
• cartridge diameter
• overall height
• stem profile and dimensions
• spline count, if present
• hot/cold side and rotation
• bottom-view picture
• any visible markings

That gives the parts team enough information to compare the old cartridge with the recommended replacement part without relying on appearance alone.

If the exact cartridge is no longer available, it may make more sense to review the current SANIKB kitchen faucet range than to force an unverified replacement into the existing faucet.

FAQs

Can I identify a faucet cartridge by diameter alone?

No. Diameter helps narrow the search, but you still need to compare height, stem profile, rotation and base features.

Can two faucet cartridges with the same diameter be different?

Yes. They may use different stems, locating pins, inlet layouts or rotation even when the bodies are the same size.

Does handle rotation matter?

Yes, especially on two-handle faucets. Record which side the cartridge came from and whether the handle opens clockwise or counterclockwise.

What if there is no part number on the cartridge?

Use the faucet brand and model if available, then measure the cartridge and take clear top, side and bottom pictures. Those details are usually far more useful than appearance alone.