Do you want to fix a leaking bathroom or kitchen faucet?
A leaking faucet can be frustrating, as it increases your water bill, produces annoying dripping noises, and may lead to mold growth around the sink.
As a home inspector, I have reported on many leaking faucets and and my clients often ask me how to fix it.
In this guide, we’ll go over:
- How to replace the faucet cartridge
- Tips to change the O-rings for a tight seal
- How to clean a faucet cartridge of mineral deposits
- Replacing rubber seats/springs of ball faucets
- And more…
Let’s get started!
Tools And Supplies Needed
- New Cartridge Or Repair Kit: Homeowners can either replace the entire faucet cartridge or use a repair kit containing O-rings, washers, and rubber seats/springs. There are also universal repair kits that come with different sized O-rings and washers which is useful for older faucets where replacements may be unavailable.
- Hex Or Allen Wrench: You will need a hex or Allen wrench if your faucet has a set screw. Typical sizes include 1/8″ or 3/32″.
- Flathead And/Or Phillips Screwdriver: A flathead screwdriver may be needed to pry off any decorative caps and to loosen/remove the cartridge. A Phillips or flathead may be needed to unfasten the screw underneath the decorative cap.
- Strap Or Adjustable Wrench: For faucets that have twist off handles, a rubber strap wrench is useful for hard-to-remove handles. An adjustable wrench (covered in tape) can also be used. An adjustable wrench will also be needed to remove the retaining nut that is secured over the cartridge.
- Plumber’s Grease: Silicone grease that is put over O-rings and bottom of cartridge.
Fix #1: Replace Cartridge
In modern faucets, leaks are most often caused by a failing cartridge. Most have a cartridge inside each handle or at the base of the faucet. Older models may use a stem or ball assembly, especially in single-handle designs.
These valves control the flow of water for the hot and cold side (dual handle faucets) and controls both water/temperature for single-handle faucets.
A faulty cartridge can cause leaks at the base of the faucet or around the handles. Replacing them is fairly simple and safe for most homeowners to do themselves. Read the steps below to change out a cartridge or ball:
Step 1: Determine Which Side is Leaking
If you have a dual-handle faucet, and you aren’t sure which faucet side (hot or cold) the leak is coming from, you can turn off one shutoff valve at a time under the sink for a quick diagnosis.
Turn the shutoff valve or angle stop clockwise until it is perpendicular to the water line. If the leak stops, then you know which hot/cold handle to repair.
Step 2: Turn Off Water Completely
I recommend completely shutting off the water to the sink. You don’t want any accidental water flow when trying to fix the leak and make a mess. Turn both hot and cold water valves clockwise or perpendicular to the water line.
CAUTION: If you have a corroded shutoff valve with evidence of rust or mineral deposits, you may want to turn off the main water shutoff for the entire house just in case the valve breaks or starts leaking.
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Step 3: Allow All Water To Drain Out
Open the faucet handle(s) and allow all remaining water to drain out. If water is still coming out of the faucet, you may have a faulty shutoff valve under the sink. I recommend turning off the main water shutoff valve to the entire home especially if there is still water coming out.
Step 4: Lay Down A Rag And Pull Up Stopper
I recommend pulling up the sink stopper so you don’t lose any parts when you disassemble the faucet.
Placing a rag or paper towel in the sink can help prevent scratches if you drop a tool.
Step 5: Remove Faucet Handle Or Base
After determining which side is leaking, homeowners will need to remove that side of the faucet handle or the center base if it’s a single-handle faucet.
Faucets are typically removed in one of three ways.
- Set Screw: There is a set screw on the side or bottom of handle that needs to be loosened with a hex or Allen wrench. There can be variation in the size but a 1/8″ or 3/32″ sized Allen wrench will usually do the trick. If you have a set of Allen wrenches, one of them should fit.
- Decorative Cap: Some faucet handles will have a small decorative cap on the top or side that will need to be removed with a flathead screwdriver or a pick. These decorative caps are typically made out of plastic and colored blue/red. Once the plastic cap is pried off, there should be a Phillips screw underneath.
- Twist Off Handle: It isn’t as common but some faucet handles won’t have a set screw or a decorative cap. You will simply need to twist off the faucet handle counterclockwise. Homeowners may be able to do it by hand, but a strap or adjustable wrench may be necessary. If using an adjustable wrench, I recommend covering it with blue painter’s tape to prevent scratches.
Step 6: Remove Retaining Nut Over Cartridge
After removing the handle, the cartridge should be visible. But before you can remove the cartridge, you will have to remove the retaining nut (or metal clip) that is holding the cartridge in place.
You can use an adjustable wrench or pliers to turn the large nut counterclockwise to loosen it and pull it off the cartridge. If there is a metal retaining clip, you can use needle nose pliers to pull it off.
Tighten Retaining Nut And Test (Optional)
Sometimes all homeowners have to do is tighten the retaining nut that is holding the cartridge in place. Over time, the retaining nut can become loose which allows the faucet to leak.
Simply tighten the retaining nut with an adjustable wrench. And then turn back on the water to that side of the faucet to see if it’s still leaking.
Step 7. Remove Faucet Cartridge
Homeowners will need to remove the faucet cartridge or ball after removing the retaining nut.
I highly recommend first taking a picture of the cartridge to remember its orientation.
Most faucet cartridges are unthreaded and should be lifted straight up by hand but you may need to use pliers or channel locks to grab the top metal piece of cartridge to pull it out.
Be aware that some cartridges and stems ARE threaded, requiring you to turn them counterclockwise for removal.
You can also use pliers for grip and gently twist it back and forth to loosen it. There are also specialized cartridge puller tools if you have a stubborn or stuck cartridge.
After removing the cartridge, look into the valve body (hole) to see if there is a rubber washer that is still in there. You may need to use an Allen wrench or pick to remove it from the hole.
Step 8: Find Correct Cartridge Type
If the cartridge is damaged, simply replacing it may be the best option.
Faucet cartridges are pretty cheap and you may want to avoid the hassle of cleaning them or changing the O-rings.
I recommend removing the faucet cartridge, and taking it to the hardware store for an exact replacement. Another option is to find the exact model number on the cartridge itself and order it online.
However, if you have an old faucet you may have trouble finding a replacement cartridge. The only option would be to be buy a universal faucet repair kit that has replacement washers, O-rings, rubber seats of various sizes.
Step 9: Apply Plumber’s Grease
Before installing the new cartridge, I recommend putting on a bit of silicone plumber’s grease over the O-rings of the new cartridge and on the bottom of it.
The plumber’s grease will help the cartridge last longer and it will help the handle move more smoothly when opened/closed.
Step 10: Install The New Cartridge
Insert the new cartridge into the valve body (hole) in the exact same orientation as when you pulled it out.
Make sure the cartridge’s slots align with those inside the opening.
Install the retaining nut back over the cartridge and hand tighten. Tighten the nut further using an adjustable wrench but be careful not to overtighten.
If the cartridge has a metal clip, use needle-nose pliers to reinstall it. Put the faucet handle over the cartridge and tighten the set screw. If there was a decorative cap, snap that back on.
Step 11: Turn On Water
Slowly turn back on the water to the faucet. Turn the faucet handle and allow water to flow for a minute to flush out any remaining debris and to purge it of air.
If the faucet is still leaking, you may have a deteriorated or broken valve seat — the female part of faucet that cartridge goes into.
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Fix #2: Replace O-Rings
For cartridge and ball faucets, the O-rings are essential parts that seal the faucet — and if damaged — can cause leaking from the handle or base.
Faucets with cartridges, the O-rings will be on the outside of the cartridge. When you pull out the cartridge, carefully inspect the O-rings for damage.
For single-handle ball faucets without a cartridge, the O-rings are on the faucet base around the spout.
If the O-rings look deteriorated, you may want first try to replace them. There are universal faucet repair kits with an assortment of different sized O-rings.
You can also pry an O-ring off the cartridge or base and take it to the hardware store to try and get an exact replacement, there is typically an entire section for O-rings in the faucet repair aisle of hardware stores.
When you put the new O-rings on, I recommend putting on plumber’s grease (typically silicone) onto the O-ring.
The plumber’s grease will help the O-rings last longer, prevent cracking, and it will also make the faucet handle smoother.
Fix #3: Tighten Loose Parts
Sometimes homeowners don’t need to replace any parts to fix a faucet leak but just tighten parts. If any of the handles are loose, it can cause water to leak around the handle or base of the faucet.
Simply locate the set screw securing the handle and tighten it with an Allen wrench.
If there is a leak at the base of the sink or even underneath the sink, tightening the mounting nut located underneath the sink can do the trick.
A loose aerator (mesh screen) on the tip of the spout can also cause unexpected leaks due to backpressure in the faucet.
Additionally, a loose retaining nut that secures the cartridge/stem to the faucet can cause leaking.
You may want to methodically tighten all these parts to see if it fixes the leak. Be careful not to over-tighten the threads because it can damage the seals and threads however.
Fix #4: Tighten, Clean, Or Replace Aerator
Occasionally, a loose, clogged, or damaged aerator — the mesh screen at the spout’s tip — can cause leaks at the base or handle, but only when the water is turned on.
A loose aerator can disrupt water flow, creating backpressure that forces water to leak from the base.
The aerator is easy to inspect and tighten. You will need to remove the aerator by twisting it counterclockwise (facing up) and inspect it for mineral deposits.
Twist it back onto the spout moderately tight (not overly tight) and check for leaks by turning on the water.
Fix #5: Replace Seats and Springs (Ball Faucets)
With some single-handle faucets, there is a ball assembly instead of a cartridge such as with Delta or Peerless brands.
The ball valve typically has 2 or 3 rubber seats and springs located underneath that controls water flow into the ball assembly.
You will need to take a flathead or small tool and pry out the rubber seat and spring from the valve seat after removing the ball.
You may need to take a paper towel and remove any existing water in the valve body to actually see the rubber seat and spring after removing the cartridge.
Correct Seat And Spring Orientation
It is essential that you install the new seat and spring in the correct orientation. The rubber seat goes over the SMALL or tapered side of the spring. And the spring side goes first into the valve body (female part of faucet that cartridge goes into).
Changing out these rubber seals and springs is an easy and cheap way to fix a leak without replacing the entire faucet.
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Fix #6: Clean The Cartridge
Sometimes all you have to do is clean the cartridge of debris caused by minerals in the water. After pulling out the cartridge, let it soak in white vinegar for about 30-min. to an hour.
Once the cartridge has been soaked, I recommend using an old toothbrush to brush away any debris. Pay careful attention to the small openings where water flows through.
If any of these holes are clogged, use a toothpick or wire to clear the hole of any minerals or debris.
After the cleaning, run the cartridge through some water to flush out any remaining particles. Re-install the cartridge and faucet handle. Turn on the water and run the faucet to see if the leak is fixed.
Fix #7: Replace Seals/Gasket Around Base
If you have leaking faucet that isn’t from the center spout but from the faucet base (below the handle or spout), read the steps below.
A leaking faucet at the base (or underneath the sink) is typically from a failed gasket or O-ring that is in-between the faucet base and the countertop.
If you have a leak from below the sink, it is likely a loose mounting nut underneath the sink that is securing the faucet to the countertop.
Step 1: Turn Off Water
Always turn off the water first before working on a sink.
Turn the shutoff valves under the sink clockwise or perpendicular to the water line.
Step 2: Allow Water To Drain Out
Open up the faucet to allow all remaining water in the faucet and water line to drain out.
If you miss this step, you may get a wet mess all over your floor.
Step 4: Disconnect Water Lines If Needed
Depending on the length of your flex water lines below the sink, you may need to disconnect them in order to lift up the sink base.
Obviously, you only want to do this if you have to.
If there is no slack in your water lines, disconnect them using an adjustable wrench.
Step 5: Loosen Mounting Nut Under Sink
Your faucet is secured to the countertop with a mounting nut underneath. Homeowners may need to use a basin wrench to loosen the nut if there isn’t any room for an adjustable wrench.
Turn the nut counterclockwise (looking up) and remove it.
Step 6: Lift Up The Faucet
After removing the mounting nut, the faucet can be lifted up to inspect the base.
Inspect the gasket or seal underneath the faucet to see if it’s cracked or worn. Replace the gasket or seal if needed and re-tighten the mounting nut.
Step 7: Turn On Water And Test
Turn on the water and check if the leak is fixed.
Signs of a Faulty Faucet Cartridge (Besides Leaking)
A leaking faucet is the most common sign that a faucet cartridge needs to be replaced, but there are other indicators such as:
Difficulty Turning Handle
If it is difficult to turn the faucet handle, if it is making grinding noises, it can indicate that the cartridge needs replacement or cleaning.
And if the handle is too loose, it can also mean a bad cartridge or the set screw needs adjustment.
Inconsistent Water Flow
When the water pressure is weak or inconsistent, it can indicate a bad faucet cartridge such as mineral deposits or faulty internal seals.
If water temperature fluctuates, it can also be a sign that there is something wrong with the cartridge since it controls water flow.
Water Delay in Shutting Off
If there is a small delay between when you turn the faucet handle to off and when water actually shuts off, it can indicate a problem with the faucet cartridge.
When the seals in the cartridge are corroded or not operating correctly, it takes longer for water to stop flowing when shut off.
How To Fix Low Water Pressure After Repair
If you fixed your leaking faucet but still dealing with low water pressure, you may need to change out the mesh screen or aerator.
The aerator is a circular screen that is on the tip of the faucet and it’s designed to mix air with the water stream. The extra air makes it feel like more water is being used but actually reduces water use.
Mineral deposits and other debris after changing or cleaning the cartridge may have clogged the aerator leading to reduced water pressure.
Typically, homeowners can just unscrew the aerator by hand by turning it counterclockwise when looking upwards at the faucet tip. You also may need to use pliers or a channel-lock wrench to loosen it.
I recommend using an old toothbrush and vinegar or you can just let it soak in vinegar for a few hours to dissolve the sediment.
Final Thoughts
If you have a leaking faucet, the easiest solution is to replace the cartridge, change out the O-rings, or to clean the cartridge by soaking it in vinegar.
A leaking faucet can waste hundreds of gallons of water over time, wear out faucet parts, and just make it difficult to use.
I hope you enjoyed this guide by TimberSill. Leave a comment below or ask me a question on fixing a leaking faucet.