A dripping faucet wastes up to 3,000 gallons of water per year and drives up your water bill month after month. Learning how to fix a leaky faucet by cartridge type saves you money and stops that annoying drip for good. The process comes down to seven steps: shut off the water, remove the handle, take out the retaining clip or nut, pull the old cartridge, clean the valve body, install the new cartridge with fresh O-rings, and reassemble everything.
Whether you have a Delta single-handle kitchen faucet, a Moen double-handle bathroom setup, or a Peerless shower valve, the cartridge repair process follows the same core steps with minor brand-specific differences. I have walked dozens of homeowners through this repair, and most finish it in under an hour with basic hand tools.
If your faucet is beyond repair and you are ready for an upgrade, check out our guide to the best bathroom faucets. You can also improve your water quality while you are under the sink by reading our recommendations for under sink water filters.
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Before you start, gather these tools so you do not have to run to the hardware store mid-repair. Most homeowners already have the basic hand tools on this list.
Allen wrench set (metric and standard) for removing set screws on lever handles
Adjustable wrench or basin wrench for loosening retaining nuts
Needle-nose pliers for pulling retaining clips and small parts
Groove-joint pliers for gripping stubborn cartridges
Cartridge puller (brand-specific for Moen, Delta, or generic stem puller)
Plumber's grease (silicone-based, not petroleum) for lubricating O-rings
Replacement cartridge kit matched to your faucet brand and model
White vinegar and an old toothbrush for cleaning mineral deposits from the valve body
Towels and a bucket to catch residual water from the supply lines
Flashlight or headlamp so you can see inside the dark cavity under the handle
Replacement cartridge kits typically cost between $15 and $40 depending on the brand. I recommend buying the kit before you start so you can compare the old and new cartridges side by side.
Here is the complete step-by-step process to fix a leaky faucet by cartridge type. Follow these seven steps in order, and take your time on each one.
Locate the shut-off valves under the sink and turn both the hot and cold valves clockwise until they stop. If your faucet does not have individual shut-off valves underneath, shut off the main water supply to the house.
Open the faucet handles to drain any remaining water from the lines. Place a towel and small bucket under the work area to catch residual water that will spill when you disconnect components.
Warning: Skip this step and you will have water spraying everywhere within seconds of removing the cartridge.
Look for a set screw on the side or back of the handle. On most single-handle faucets, this is a small Allen screw hidden under a decorative cap. Pop the cap off with a fingernail or small flathead screwdriver, then loosen the set screw with the matching Allen wrench.
For double-handle faucets, pry off the hot or cold cap on top of the handle to reveal a Phillips screw. Remove the screw and lift the handle straight up. If the handle is stuck from mineral buildup, wrap a rag around it and gently rock it back and forth while pulling upward.
Once the handle is off, slide off any decorative escutcheon rings or domes that cover the cartridge assembly.
With the handle removed, you will see either a brass retaining nut threaded over the cartridge or a metal retaining clip sliding through the side of the valve body. Your faucet will have one or the other depending on the brand.
For a retaining nut (common on Delta and Peerless faucets), use an adjustable wrench to turn the nut counterclockwise until it comes free. For a retaining clip (common on Moen faucets), grab the top of the clip with needle-nose pliers and pull it straight up.
Forum users on r/HomeImprovement frequently mention forgetting the second retaining clip on two-handle setups. Check both sides carefully before moving on.
Grab the top of the cartridge with groove-joint pliers and pull straight up with steady, even pressure. If the cartridge resists, do not yank sideways because you can crack the valve body.
For stubborn cartridges, use a brand-specific cartridge puller. A Moen cartridge puller threads into the cartridge and gives you leverage to pull it free without damaging the brass valve body. If you do not have a puller, try gently twisting the cartridge back and forth while pulling upward.
Take the old cartridge to your hardware store so you can match it exactly. Even a small difference in height or stem length means the replacement will not seat properly.
Shine your flashlight into the valve body cavity and look for mineral buildup, debris, or corroded brass. Use an old toothbrush dipped in white vinegar to scrub away calcium deposits around the valve seat.
Check the rubber seats and springs at the bottom of the valve body (on Delta-style faucets). If they are worn, cracked, or flattened, replace them with the parts from your cartridge kit. Even a perfect new cartridge will leak if the seats below it are damaged.
Rinse the cavity with a small splash of water and dry it with a cloth before moving on.
Apply a thin coat of silicone plumber's grease to the O-rings on the new cartridge. This helps the cartridge slide in smoothly and prevents the O-rings from twisting or tearing during installation.
Align the new cartridge with the notches or tabs inside the valve body. Most cartridges have a flat side or a keying tab that must line up with a corresponding slot. Push the cartridge straight down until it seats fully at the bottom of the valve body.
Reinstall the retaining clip by sliding it back through the hole in the valve body until it clicks into place. If your faucet uses a retaining nut, thread it on clockwise and tighten it snugly with your wrench. Do not overtighten because you can crack the plastic cartridge body.
Replace any decorative escutcheon caps, then reattach the handle. Tighten the set screw or Phillips screw snugly without forcing it. Pop the decorative cap back over the screw hole.
Turn the shut-off valves back on slowly. Open the faucet and let water run for about 30 seconds to flush out any trapped air or debris. Cycle the handle through hot and cold several times to confirm smooth operation.
Close the faucet and watch the spout for two minutes. If the drip is gone, you are done. If it still leaks, jump down to the troubleshooting section below.
The most common question I hear from homeowners is how to identify which cartridge their faucet uses. This is the single biggest stumbling block in the repair process, so let me break it down.
Single-handle cartridge faucets use one tall cylindrical cartridge that controls both temperature and flow with a single lever. Double-handle cartridge faucets use two shorter cartridges, one for hot and one for cold, each controlled by its own knob.
If your faucet has one lever or knob, you have a single-handle cartridge. If it has two knobs or levers, you have double-handle cartridges.
Delta: Delta cartridges usually have two or three rubber seats with small springs at the bottom of the valve body. The cartridge stem has a distinctive diamond or teardrop shape. Delta single-handle cartridges are among the easiest to find replacements for.
Moen: Moen cartridges are tall, white or brass cylinders with a flat side on the stem. The Moen 1225 and 1225B are the most common single-handle cartridges in North America. Moen uses a brass retaining clip that slides through the valve body sideways.
Peerless: Peerless is a Delta-owned brand and uses nearly identical cartridge designs. If you cannot find a Peerless-branded kit, a Delta cartridge kit will usually fit.
Kohler: Kohler cartridges vary widely by model. Check the model number printed on the escutcheon plate or look it up on Kohler's website using a photo of your faucet.
Reddit users on r/plumbing strongly recommend taking photos of your faucet from multiple angles before heading to the hardware store. Bring the old cartridge with you in a zip-top bag. Hardware store staff can usually identify the exact replacement from the physical part faster than from a photo.
If you cannot find a match locally, search by brand and model number online. Most manufacturers sell direct replacement kits that ship within a few days.
Sometimes the cartridge itself is fine and the leak comes from worn O-rings or damaged seats and springs. Replacing just these smaller parts costs under $10 and takes about 20 minutes.
If your faucet leaks from the base of the handle rather than the spout, the culprit is usually the O-rings on the cartridge stem. Pull the cartridge out, remove the old O-rings with a pick or flathead screwdriver, and roll new ones into place.
Coat each new O-ring with a thin film of silicone grease before reinstalling the cartridge. Petroleum-based grease degrades rubber over time, so stick with silicone.
Delta and Peerless faucets use small rubber seats with cone-shaped springs underneath them. These sit at the bottom of the valve body and create the seal between the cartridge and the water inlet ports.
Use needle-nose pliers to pull out the old seats and springs. Drop the new springs in first (small end down), then press the rubber seats on top. A dab of plumber's grease on the tip of a screwdriver helps hold each seat in place while you position it.
If you are also replacing the thermostatic shower valves in your bathroom, the seats-and-springs concept is similar but the cartridges are larger and more complex.
Even when you follow every step correctly, things can go wrong. Here are the most common issues and how to solve them.
If your faucet still drips after installing a new cartridge, the most likely cause is damaged seats and springs at the bottom of the valve body. Remove the cartridge again and inspect the seats for cracks, flattening, or mineral pitting. Replace them from the kit.
Another common cause is debris trapped between the cartridge and the valve seat. Flush the cavity thoroughly, scrub it with vinegar, and reseat the cartridge.
In rare cases, the valve body itself has corroded or cracked. If the brass is visibly pitted, you may need to replace the entire faucet.
If turning the handle to the left gives you cold water instead of hot, you installed the cartridge 180 degrees backwards. Remove the retaining clip or nut, pull the cartridge out, rotate it halfway, and reinstall it. Some cartridges have an arrow or label indicating which side faces hot.
This is a harmless mistake that takes two minutes to fix once you know what happened.
A cartridge that will not budge is the most frustrating part of this repair. Pour white vinegar around the base of the cartridge and let it soak for 30 minutes to break down mineral deposits. Then use a cartridge puller for controlled, even force.
If the cartridge still will not come free, tap the top of the cartridge stem gently with a wooden handle to break the corrosion bond. Never use a metal hammer directly on the cartridge because it can shatter the plastic and send fragments into the valve body.
If the new cartridge stops short of seating flush in the valve body, check for a misaligned tab or notch. Pull it back out and look for the alignment mark. Make sure no old O-rings or debris are stuck at the bottom of the cavity blocking the seat.
A few simple habits extend the life of your faucet cartridges and delay the next repair.
Check your home water pressure with a gauge attached to an outdoor spigot. Pressure above 80 psi stresses faucet internals and shortens cartridge life. If your pressure is high, install a pressure regulator on your main supply line.
Clean aerators and showerheads every few months by soaking them in vinegar overnight. This prevents mineral deposits from working their way back into the valve body and scratching the cartridge seals.
Listen for changes in how the handle feels. A handle that suddenly becomes stiff or requires extra force to turn signals early cartridge wear. Replacing the cartridge at the first sign of stiffness prevents a full leak from developing.
Most cartridge faucet repairs are well within a DIYer's ability. But there are situations where calling a licensed plumber is the safer and more cost-effective choice.
If the valve body is visibly corroded, cracked, or leaking from somewhere other than the cartridge opening, the problem extends beyond a simple cartridge swap. A plumber can assess whether the valve body can be salvaged or if the faucet needs full replacement.
If you have replaced the cartridge, seats, springs, and O-rings and the faucet still leaks after two attempts, call a professional. Repeated failures usually point to an issue with the supply lines, water pressure, or the valve body itself that requires diagnostic tools most homeowners do not own.
A typical plumber visit for a cartridge faucet repair runs $120 to $250 depending on your location. Compare that to the $15 to $40 cost of doing it yourself, and you can see why most people try the DIY route first.
To fix a leaky cartridge faucet, shut off the water supply, remove the handle, take out the retaining clip or nut, pull the old cartridge, clean the valve body, install a new cartridge with fresh O-rings coated in silicone grease, then reassemble and test. The entire process takes under an hour with basic hand tools and a replacement cartridge kit.
Identify your cartridge by first determining if you have a single-handle or double-handle faucet. Then check the brand name printed on the handle or escutcheon plate. Delta cartridges use seats and springs, Moen cartridges are tall cylinders with a flat-sided stem, and Peerless uses Delta-compatible parts. Take the old cartridge to the hardware store for an exact match.
A faucet that still leaks after a cartridge replacement usually has damaged seats and springs at the bottom of the valve body, trapped debris between the cartridge and the seat, or a corroded valve body. Remove the cartridge, inspect and replace the seats and springs, clean the cavity with vinegar, then reseat the cartridge carefully.
Yes, if the leak comes from the handle base rather than the spout, replacing just the O-rings on the cartridge stem often solves the problem. Remove the cartridge, swap the old O-rings for new ones coated in silicone plumber's grease, and reinstall. This costs under $10 and takes about 20 minutes.
Fixing a leaky faucet by cartridge type is one of the most rewarding DIY plumbing repairs you can tackle. With about an hour of work, a $15 to $40 replacement kit, and a few basic tools, you can stop the drip, save thousands of gallons of water per year, and avoid a plumber's bill.
The key is identifying your cartridge correctly before you buy parts, cleaning the valve body thoroughly during installation, and testing carefully before you declare victory. If you run into trouble, the troubleshooting section above covers the most common post-repair issues.
If your current faucet has seen better days and a cartridge swap is not enough, explore our recommendations for the best bathroom faucets to find a replacement that will serve you well for years.