What Size Shower Cartridge Do I Need? How to Measure and Match It
The part number on an old shower cartridge is often scaled over, worn away or never printed at all. Size helps, but it is rarely enough on its own: the few lengths that makers publish sit within a fraction of an inch of each other. The surest way to name a single-handle shower cartridge is to collect a handful of clues, then measure the old part to confirm them. If you already know the brand of your shower, our cartridge identification guide goes brand by brand.
Moen's 1222 instructions say to always turn the water supply off before disassembling the valve, then open the handle to relieve pressure and make sure the water is off. Delta, Kohler and Pfister instructions also start by shutting off the water. Some valves have their own shutoffs behind the trim: Moen's Posi-Temp stop checks turn with pliers or a flathead screwdriver, and Kohler sells Rite-Temp valves with or without screwdriver stops. Where there are none, Moen says the shutoff may be the main for the house. Delta warns: do not pry the cartridge out of the body with a screwdriver. Moen says not to force a retainer clip back in, and if the clip will not go in or looks damaged or broken, the water cannot be turned back on until the clip is replaced.
Five clues before you measure
Each clue narrows the field. Together they usually leave one or two candidates, and the measurements settle it.
- The brand on the trim. SupplyHouse suggests checking the trim plate, the handle cap and the back of the handle, and Family Handyman says to look on the handle or trim for the brand. SupplyHouse also notes that many brands use more than one cartridge, so the brand narrows the search without ending it.
- How the handle works. Moen lists its Posi-Temp 1222 handle as rotate only, with no volume control. Its 1225 handle pulls out to turn the water on, pushes in to turn it off and rotates to set the temperature. Moen's M-Core valves work the same two ways but take different cartridges (the 1212 and 1213), so check the trim too: Moen says a Posi-Temp valve has two escutcheon screws at the 2:00 and 7:00 positions.
- Marks on the valve body. SupplyHouse says to take the handle off and look for a model number stamped on the valve body. Body names matter: Pfister, for example, lists its 974-5299 cartridge for VB8 and JV8 bodies and as backward compatible with its older 0X8 and JX8 cartridges.
- The series, the date and the color. Delta lists the RP46074 for MultiChoice 13/14 Series showers produced after March 2006 and the RP19804 for Monitor 1300/1400 Series showers produced before March 2006. Delta describes the RP19804 as blue and white and the RP46074 as gray. Treat the date as a guide only: Delta's own cartridge summary sheet shows 1300/1400 cartridges shipped in July 2006 or later that still take the RP19804, and shows the RP19804 with a shorter lower housing than the RP46074.
- Anything printed on the cartridge. Look on the front and back of the cartridge for a number or letters (our own tip). Danco says to photograph the parts in the order you removed them.
How to measure the old cartridge
Measure the cartridge once it is out of the valve. DEA Bath, a parts supplier, says it cannot identify a stem that is still in the valve. It prefers calipers to a tape, and so do we: a cartridge is small enough that a sixteenth of an inch matters. Our own tip: write down each number in inches and millimeters.
- A, overall length. Measure end to end, stem tip to base, as DEA Bath says.
- B, body diameter. Measure across the widest part of the body. This one is our own addition to DEA Bath's list.
- C, stem diameter. DEA Bath measures the smooth shank under the splined end.
- D, splines. DEA Bath says to count the splines, the ridges the handle grips. On a square stem, measure flat to flat, not corner to corner.
We also suggest noting what held the cartridge in (a clip, a nut, a cap or screws), its colors and any letters on it. Then take the old cartridge with you to the store, as Family Handyman and SupplyHouse both suggest.
The lengths makers publish
Most maker part pages we opened give no dimensions at all. The ones we found show why the length alone is a weak clue.
Delta's two cartridges are 5/16 inch apart, and Delta says they are not interchangeable, so check the install date and the color too. Pfister's length depends on the valve: its instructions use an adapter and seal when the valve has a depth of 2 inches, and no adapter at 1-27/32 inch.
Match it to the shower cartridges we sell
Check your clues against the whole row, then open the part page for the fit list.
| Cartridge it replaces | Valve | Clues to check | FourHome part |
|---|---|---|---|
| Moen 1222 | Moen Posi-Temp single-handle tub and shower | Handle rotates only. Two escutcheon screws at 2:00 and 7:00. Held by a retainer clip; Moen loosens it with a plastic twisting tool, then pulls it with pliers. | Replacement for Moen 1222 |
| Moen 1225 | Moen single-handle tub and shower, Standard and Moentrol valves | Handle pulls out for on and rotates for temperature. Held by a copper clip. | Replacement for Moen 1225 kit |
| Delta RP46074 | MultiChoice 13/14 Series, after March 2006 | Gray. 4-7/16 in. overall height. Under a bonnet nut. | Replacement for Delta RP46074 |
| Delta RP19804 | Monitor 1300/1400 Series, before March 2006 | Blue and white. 4-1/8 in. overall height. Under a brass bonnet. | Replacement for Delta RP19804 |
| Kohler GP500520 | Kohler Rite-Temp K-304 | A pressure balancing unit under the mixer cap. Kohler takes the cap off, then pulls the unit with pliers. | Replacement for Kohler GP500520 or replacement kit for GP876851, with a new cap |
| Pfister 974-042 or 974-5299 | Pfister 0X8 series, VB8 and JV8 bodies | 4-1/8 in. with the deep casting adapter, 4 in. without. | Replacement for Pfister 974-042 |
| Gerber 97-022 | Gerber Safetemp | Retailers list a different cartridge, 95-154 or 95-152, for Safetemp II valves. | Replacement for Gerber 97-022 |
| Grohe 47080000 | Grohe (35 000) Series pressure balance | Grohe lists it for that series with a 1/2 in. connection. | Replacement for Grohe 47080000 |
| Mixet MS-5AT | Mixet single lever, after 1968 | Retailers list the MS3T for valves made before 1968. Retailer lengths disagree, so compare the shape. | Replacement for Mixet MS-5AT |
Clues from Moen, Delta, Kohler, Pfister and Grohe pages. The Gerber and Mixet rows come from retailer listings, because we could not open a maker page for them.
If nothing matches
- Take the old cartridge and your photos to a plumbing supply counter, as SupplyHouse and Family Handyman suggest.
- If your shower has two or three handles, each handle has its own stem or cartridge (Moen, for example, lists a 1224 cartridge for its two and three handle showers), so the single-handle clues above do not apply. Danco starts every search by counting the handles. Our stem and cartridge finder covers both.
- Our sister site keeps an index of stems and cartridges you can search by part number, length and broach count.
When to stop and call a plumber
Each of these is our own advice, not a maker rule. This Old House's plumber Richard Trethewey describes the risk of forcing a stuck cartridge: "I could break it and leave parts inside the wall."
- The cartridge will not come out with the maker's tool or method.
- You cannot find a shutoff that stops the water to the shower.
- Part of the old cartridge breaks off inside the valve.
- Water shows inside the wall or behind the trim, not only at the spout or showerhead.
Frequently asked questions
Can I identify a shower cartridge by its length alone?
Rarely. Delta lists the RP46074 at 4-7/16 inch overall height and the RP19804 at 4-1/8 inch, and says the two are not interchangeable. Use the brand, the handle action, the valve markings and the color as well, then use the length to confirm.
Do I have to take the cartridge out to measure it?
For the length and the spline count, yes. DEA Bath, a parts supplier, says it cannot identify a stem that is still in the valve. You can collect the other clues first: the brand on the trim, how the handle works and any marks on the valve body behind the trim.
What should I measure with?
Calipers if you have them. DEA Bath prefers calipers and says to measure the stem end to end, count the splines and measure the smooth shank under them. On a square stem, measure flat to flat, not corner to corner.
Is a Moen 1222 the same as a Moen 1225?
No. Moen describes the Posi-Temp 1222 handle as rotate only, while the 1225 handle pulls out to turn the water on and rotates to set the temperature. SupplyHouse, a retailer, says the 1222 does not fit the Moen 1225 system. Moen M-Core valves use the same two handle actions with different cartridges, so check the escutcheon screws and the cartridge as well.
My Delta shower has no date on it. Which cartridge does it take?
Go by the series and the cartridge more than the year. Delta lists the RP19804 for Monitor 1300/1400 Series showers made before March 2006, but its own summary sheet shows 1300/1400 cartridges shipped in July 2006 or later that still take the RP19804. Delta describes the RP19804 as blue and white with a shorter lower housing, and the RP46074 as gray with a longer one. If you need help finding your model number, Delta points to its Product Identifier Tool.
Sources
The clues and steps above come from these pages, except where the text says the advice is our own. We opened each one on October 12, 2026. Retailer pages are used only where no maker page we opened covered the point.
- Moen, 1222 installation instructions INS746J, 1222 cartridge, single handle shower, Faucet cartridges: shower, 1225 cartridge, single handle shower, How to turn off the water supply and Posi-Temp stop check valves.
- Delta, RP46074, RP19804, MultiChoice 13/14 Series instructions, 1300/1400 Series instructions and tub and shower cartridges.
- Kohler, Rite-Temp K-304 service part instructions and Rite-Temp valve spec sheet.
- Pfister, 974-5299 spec sheet and 0X8 tub and shower cartridge instructions, both hosted by Lowe's.
- Grohe, 47080000 pressure balance valve cartridge.
- Danco, How to find the right shower stem or cartridge.
- SupplyHouse, How to replace a shower cartridge; Family Handyman, Shower faucet leaking? Here's how to fix it; This Old House, How to replace a shower cartridge.
- DEA Bath, How to correctly measure your faucet stem.
- Retailer listings: SupplyHouse, Moen 1222; NYRP, Gerber 97-022 and Gerber 95-154; Ferguson, Mixet MS5AT and Mixet MS3T.
Replacement cartridges for Moen, Delta, Kohler, Pfister, Gerber, Grohe and Mixet single-handle showers, sold through the FourHome Amazon store.
See the full FourHome assortment on AmazonFourHome is an independent brand and is not affiliated with Moen, Delta, Kohler, Pfister, Gerber, Grohe, Mixet, Danco, DEA Bath, SupplyHouse or the other publishers cited. Brand names and part numbers are used only to identify fit or to cite their published instructions. Shut the water off first, do not pry or force a cartridge, and call a licensed plumber for anything beyond a cartridge swap.
FourHome is not affiliated with or endorsed by any faucet manufacturer. Brand names and part numbers are used only to identify compatibility.