Leaky Single-Handle Faucet? Find the Leak, Then Fix the Right Part
A single-handle sink faucet mixes hot and cold through one valve, so most drips come back to the part inside it. Moen puts it plainly: if a faucet is leaking water from the spout, the reason is usually the cartridge. But not every leak is the cartridge, and which part you need depends on where the water shows and what you find under the handle. This guide covers single-handle kitchen and bathroom sink faucets. If your Moen kitchen faucet uses the 1200 or 1225 cartridge (Moen uses others too), our kitchen faucet guide has every step.
First, find where the water comes from
Our own first step: dry the faucet and the deck around it with a towel, run the faucet, shut it off and watch where water shows first.
| Where you see water | What it usually means | What to do |
|---|---|---|
| 1. Drips from the spout with the faucet shut off | Moen: usually the cartridge. On a ball faucet, Delta points to worn seats and springs. | Replace the cartridge, or the seats and springs on a ball faucet. |
| 2. Around or under the handle | It depends on the faucet. Moen says usually the cartridge. Glacier Bay lists a loose bonnet nut or a dirty or damaged washer. Zurn says to snug the cartridge retaining nut. | Take the handle off. If a nut holds the cartridge, snug it without over tightening. If it still leaks, shut the water off and check the cartridge and its O-rings. |
| 3. At the base of the spout | On a Moen kitchen faucet with a standard swivel spout: a torn or scratched O-ring inside the spout. On a pullout or pulldown faucet, the vacuum breaker in the spout receptor may not be sealing. | Replace the spout O-rings. Moen says the size and count vary by model. |
| 4. Under the sink | Moen: the shutoff valves, the house supply lines or the faucet hose connections. Zurn: a loose aerator can leak along the waterway and show up under the sink. | Usually not the cartridge. Tighten the aerator, then check each connection. |
Moen says a handle leak can puddle onto the base plate and look like a leak at the base of the faucet. Wrap a paper towel around the handle and turn the faucet on: if the towel gets wet, the leak is at the handle. Our sister site walks through more checks for a faucet leaking at the base or under the handle.
Moen says any repair on its faucets requires the water supply to be shut off, and that failure to do so could result in flooding or injury. Turn both shutoffs under the sink clockwise until they are tightly closed, then open the faucet to make sure the water is off. If a shutoff is stuck, Lowe's says to shut off the main instead. Our own advice: do not force it. If the water still comes on, This Old House says to shut it off at the next valve down the line or at the main. Cover the drain so small parts cannot fall in, as Glacier Bay and Delta both say.
Then see what is under the handle
This Old House pries off the decorative cap, removes the handle screw and pulls the handle off. On some faucets the screw is a set screw behind a plug button: Symmons removes the plug button and loosens the set screw, and Delta loosens its set screw with an Allen wrench. Moen lists the handle screw on its 1225 faucets either under a cap on top of the handle or behind a plug button in front. Lowe's suggests laying the parts in order and taking a photo as you go.
- A cartridge held by a clip. Moen lists the retainer of its 1225 cartridge as a U-shaped copper clip and says the 1225 is common in Moen single-handle faucets made before 2009. Not every Moen uses the clip: Moen also lists a newer cartridge held by a brass nut.
- A ceramic disc cartridge under a nut, ring or screws. Danco says some cartridges have a retainer nut, a retainer clip or screws that hold them in place. Glacier Bay lists a bonnet nut over its cartridge, Zurn a retaining nut, and Symmons holds its KN-4 cartridge with a compression ring under a cap.
- A ball. Delta's ball faucets have a cap, then a cam and packing over a ball, with seats and springs below. This Old House says that if your faucet does not have a stainless-steel ball, it is likely a ceramic-cartridge faucet. To stop a spout drip on a ball faucet, Delta lifts out the cam, packing and ball, removes the seats and springs, and sets new seats over new springs (RP4993) in the sockets in the body. Delta warns that over tightening the adjusting ring can wear the seal surfaces early.
Replace a ceramic disc cartridge
These steps follow the Symmons and Zurn instruction sheets, the Glacier Bay care guide and Danco's cartridge guide. Where your faucet's own sheet differs, follow the sheet. For Glacier Bay 35 mm cartridges we have a step-by-step guide with photos.
Step 1: Water off, faucet open, drain covered
As in the box above. Symmons and Zurn both start by shutting off the hot and cold supplies.
Step 2: Take off the handle
Pop the plug button or cap, loosen the set screw and lift the handle off. Symmons removes the plug button, loosens the set screw and removes the handle.
Step 3: Remove the cap and the nut or ring
Unscrew whatever holds the cartridge down. Symmons engages its cartridge wrench in the slots of the compression ring and turns it counterclockwise until the cap and ring come off the body. On a Glacier Bay faucet it is the bonnet nut. Danco notes that some cartridges use screws or a clip instead.
Step 4: Note the position, then pull it straight up
Take a photo of how the cartridge sits before you move it. Danco lifts the cartridge out of the faucet body and, if it is stuck, says to gently grab it with the pliers and pull it out. Our own advice: pull straight up, do not force it, and if it will not come out, see the last section.
Step 5: Clean the faucet body
Danco says to thoroughly clean the inside of the faucet body before installing the new cartridge, and to replace rubber seals that are damaged or cannot be cleaned. Moen recommends cleaning and flushing the valve body, because debris could damage the new cartridge or obstruct the flow of water. Moen warns that water may come out of the open valve body with considerable force, so one person holds a large bowl upside down over it while a second person turns the water on slightly, one side at a time. Symmons says to flush the supply lines so grit does not reach the cartridge sealing surfaces.
Step 6: Seat the new cartridge
If you grease the O-rings, use silicone grease. Moen says not to use plumber's grade faucet grease, silicone sprays or any lubricant that may contain petroleum, because petroleum-based lubricants may react with the rubber seals.
Set it in the same position as the old one, as This Old House says. Symmons matches the posts in the base of the cartridge with the alignment holes in the valve body and keeps the three-ring seal in place, and Danco lines up the tabs or pegs on the cartridge with the notches or holes in the faucet body. Our own advice: it should sit flat without force.
Step 7: Snug the nut, do not crank it
Zurn says: do not over tighten, tighten until the nut is snug. Symmons threads its cap on firmly by hand, with no wrench on the cap, and turns the compression ring finger tight and then 1/4 to 1/2 turn further with its wrench.
Step 8: Water on, then test
Put the handle back on; Symmons says to reassemble in reverse order. With the handle in the off position, Glacier Bay says to turn the water supply on and check for leaks, then let the water run for at least one minute. Zurn takes the aerator off, opens the faucet to the mixed position for a minute and checks for leaks under the sink.
Step 9: Reset the limit stop
Some ceramic cartridges, including the Symmons and Zurn ones, have a limit stop that sets how far the handle turns toward hot. Both makers set it with the water running. Symmons says to set its hot water limit stop after replacing the cartridge: run the faucet at full hot, and if the temperature is wrong, take the handle off, lift the limit stop ring with a small flat screwdriver and rotate it clockwise if the water is not hot enough, counterclockwise to lower the temperature. Zurn removes the handle and the stop, turns the water on, sets the maximum temperature (clockwise raises it) and refits the stop so the lug on the cartridge touches the lug on the stop. Then put the handle back on. Other brands can differ, so follow your faucet's sheet.
Moen 1200 and 1225 cartridges
A clip-held Moen cartridge comes out differently. Moen slides the copper clip out of the valve body, loosens the cartridge with a quarter turn of its plastic twisting tool and pulls it by the stem with pliers, which may require some effort. Its 104421 cartridge puller also removes 1200, 1225 and 1222 cartridges. When the new cartridge is in, Moen says to slide the clip back gently and not to force it if you feel resistance. If the clip cannot be installed or appears damaged, Moen says the water cannot be turned back on until the clip is replaced. If hot and cold come out reversed, Moen says to rotate the stem 180 degrees, without removing the cartridge. Our kitchen faucet guide has the full steps, and our Moen cartridge comparison helps if you are not sure which one you have.
If the cartridge itself is sound, Moen's 92451 kit rebuilds an existing 1225 cartridge with new grommets and O-rings; a new cartridge is not provided. Moen warns that too much grease on the small O-rings can cause handle drop, where the handle will not stay open.
When to stop and call a plumber
- On a ball faucet, Delta says that if you notice the cam turning while you unscrew the cap, quit turning immediately and call a plumber.
- Delta also says to replace the entire faucet if the liners are missing, damaged or sticking up above the brass valve body.
- The shutoffs under the sink do not stop the water, or they leak when you turn them. Our own advice: have a plumber replace them before you open the faucet.
- The cartridge will not come out with the maker's tool or method, or part of it breaks off inside. Our own advice: stop there and call a plumber.
- Water keeps showing under the sink after you have checked the aerator and the connections. Our own advice: call a plumber.
Frequently asked questions
Why does my single-handle faucet drip after I turn it off?
Moen says that if a faucet is leaking water from the spout, the reason is usually the cartridge. On a ball faucet, Delta points to worn seats and springs. Either way, the handle has to come off to reach the part.
My faucet leaks at the base of the spout. Is that the cartridge?
Usually not. Moen ties a leak at the bottom of the spout to a torn or scratched O-ring inside the spout, and on pullout or pulldown faucets to the vacuum breaker. Moen also says a handle leak can puddle onto the base plate, so wrap a paper towel around the handle and run the faucet to check.
Can I replace only the O-rings?
Sometimes. Moen sells a kit that rebuilds an existing 1225 cartridge with new grommets and O-rings, and Danco says to replace rubber seals that are damaged or will not clean up. On a Moen kitchen faucet without a pullout or pulldown spray, Moen says new spout O-rings should fix a leak at the bottom of the spout. If a cartridge still drips after new seals, our own advice is to replace the cartridge.
Hot and cold are reversed after I put in a new cartridge. What now?
On a Moen 1225, Moen says to rotate the stem of the cartridge 180 degrees and that it is not necessary to remove the cartridge. On other cartridges, shut the water off and check that the new one went in at the same position as the old one, with its posts or tabs in the holes in the faucet body.
What grease should I use on the O-rings?
Silicone grease. Moen recommends silicone-based grease and says not to use plumber's grade faucet grease, silicone sprays or any lubricant that may contain petroleum. Danco also uses silicone grease on the rubber parts of a cartridge.
Sources
The checks 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 we could not open a maker page.
- Moen: Bathroom faucet dripping from the spout, Kitchen faucet leaking around the handle, Leaking around the base, Leaks at the bottom of the spout, Leaking under the sink, How to turn off the water supply and Valve body cleaning and flushing.
- Moen: Faucet cartridges: kitchen, 1225 cartridge: kitchen faucet, Reverse hot and cold for a 1225, Using a 104421 cartridge removal tool and 92451 cartridge service kit.
- Symmons, Symmetrix S-20 installation and service instructions; Zurn, Z7440 single handle lavatory faucet instructions; Glacier Bay, single-handle lavatory faucet installation and care guide. All three hosted by The Home Depot.
- Delta, What do I do if my lavatory faucet drips from the aerator?.
- Danco, How to repair a leaky single handle cartridge faucet.
- This Old House, How to repair a dripping single-handled faucet and How to repair a leaky kitchen faucet; Lowe's, How to repair a leaky single-handle faucet.
Replacement cartridges, seats and springs and repair kits for Moen, Glacier Bay, Symmons, Delta and more, sold through the FourHome Amazon store.
See the full FourHome assortment on AmazonFourHome is an independent brand and is not affiliated with Moen, Glacier Bay, Symmons, Zurn, Delta, Danco, The Home Depot, Lowe's 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 force a cartridge, and call a licensed plumber for anything beyond a cartridge or seal swap.
FourHome is not affiliated with or endorsed by any faucet manufacturer. Brand names and part numbers are used only to identify compatibility.