Faucet Still Leaks After Replacing Stem: Here’s A Quick Fix

If your faucet still leaks after replacing the stem, it’s probably the O-rings at fault. Luckily, that’s a quick fix, and almost anyone can do it with a few minutes of time and the right supplies. 

Replacing the stem on your faucet can fix a lot of problems with leaks. But, if you’ve just replaced yours and it’s still leaking, there are several other culprits. Simply replacing the O-rings will likely do the job. Otherwise, you might want to replace the faucet handle valve or assembly. 

4 Major Reasons Why You’re Bathtub Faucet Is Still Leaking 

It can be disheartening to learn that your bathroom faucet is still leaking after you’ve just replaced the valve stem. But, luckily, there are only a few possible reasons and all of them are easy to diagnose. 

Poorly Installed Valve Stem 

The first consideration is that you might have installed the new valve stem badly. For example, if the valve stem isn’t screwed in properly. Or, if the valve stem doesn’t quite fit into the faucet body. This won’t necessarily be your fault. For example, if there’s corrosion in the faucet body, the new valve stem might not be able to securely fit in. On the other hand, if the valve stem is slightly the wrong size or has a different thread end, it quite simply might not fit. For example, valve stems are sold with splined, square broach, and threaded ends. You have to ensure your valve stem matches your faucet. In some cases, you also want to use a sealant when installing your valve stem. For example, PTFE tape, and in enough volume to facilitate a snug and watertight connection. 

Quick Checks:

  • The valve stem is installed straight, with no slight tilt to either size
  • The valve stem is fully screwed into the faucet body 
  • There are no gaps around the connector 
  • There are no cracks or gaps in the brass or ceramic (depending on what type of valve stem you have)
  • The faucet body fully closes around the valve stem 

If all of those can be answered no, you can run one final check. Turn the water on and check that water is not coming out around the tip of the valve stem. If not, you can move on to the next diagnostic. 

Valve stems may also be called cartridges depending on which part of the U.S. you live in. 

Corroded O-Rings

O-Rings are the most likely problem with your new valve stem. These O-rings, which are also called rubber washers or toric joints, are the rubber rings between the base of the faucet and the wall. O-rings and washers compress during usage. Every time you turn the valve on and off to use your bathtub, the washers will thin further. So, the more you use it and the more water you run through your bathroom, the more likely you have this issue. In fact, the higher your water pressure, the more likely they are damaged. Once they become too thin, the washer will no longer seal. 

Of course, age isn’t the only reason your O-rings might be leaking. You might also have other problems. For example, your O-rings might be a poor fit for the new valve or faucet. Or, the O-ring or washers might have built-up lime-scale. Finally, the rubber might have attracted mold or a fungus, which can eat the rubber and create holes. Any of these problems could result in a leaking O-ring. 

How do you diagnose it? If your faucet is leaking around the base, this is very likely the cause of the issue. However, you can always take the handle(s) off to check the O-ring and washers. Worst case scenario, a replacement will cost you a few minutes and a few dollars. 

Faucet Handle Problems

The faucet handle valve and assembly are the most complicated part of the faucet mechanism. Here, you might experience leaks because of a loose screw, because of corrosion, or because of damage to the assembly. That might be lime build-up or scale. It might also be bends or nicks from transport or from dropping the assembly during installation. Eventually, this problem is less likely than the other two. 

If it is the case, water might come out through the handles. However, it might also come out through the base of the faucet. Or, in some cases, it might also cause a steady tap drip – if the faucet assembly no longer closes fully. You can take the assembly apart and clean it to ensure corrosion or lime buildup aren’t causing issues. If you see physical damage like bends or nicks near ends, it’s always a good idea to simply replace it. 

Water Pressure is Too High 

If you have high water pressure, it will cause more leaks than normal water pressure. You can resolve this issue using PTFE tape or another plumber’s fixative. However, high water pressure also results in faster-than-normal damage to washers, O-rings, and assemblies. It’s a good idea to double check that there isn’t damage or compression on any of the other elements if your water pressure is very high. 

Fixing A Bathtub Faucet Leaking After Stem Replacement

Fixing your bathtub faucet leak is probably relatively easy. In most cases, the issue will be the O-ring. That’s especially true if it’s still leaking after replacing stem or cartridge elements of the faucet. 

Things You Will Need

  • A screwdriver, most likely a Flat #2 but check your faucet
  • Adjustable wrench 
  • New O-Rings (in the same size as your faucet, for the best results, take your faucet apart first and take the O-ring to the store). Please note, your cartridge or valve stem may have one or two O Rings. Make sure you replace all of them. 
  • New washers (these are less likely to be damaged, but they cost very little. Replace them anyway to be sure. Like with the O-ring, take your existing washers to the store to ensure you get the same size parts)

How to Replace an O Ring in a Bathtub Faucet

If your O Rings are faulty, the hardest part about replacing them is buying new ones. You’ll want to take your faucet apart, remove the O Rings, and then go to the store for a new one. From there, reinstallation should take a few minutes at most. Make sure you have the water to the bathroom turned off before you start this process. 

Remove the Handles 

Remove the plastic caps over the tip of your faucet handles and unscrew them. These are normally Phillips #1 or #2 or Flat #2. However, manufacturers do not use standards so they could be anything. Always check before acquiring a screwdriver. 

To remove the handles, simply undo the screws and then pull the handles off. Make sure you reserve the caps and the screws in a bag or tray so they do not get lost. Remove the escutcheon plate at this time and place it with the handles. 

Importantly, if your bathroom faucet has two handles, simply repeat this step for both.

Optional: Remove the Faucet Body 

If your valve stems are connected into the faucet body, you may have to remove the faucet body. Different models may attach the valve stem directly into the faucet body (e.g., if you have a faucet handle in the faucet body) or separately. If the handles or knobs are completely separate from the faucet body, skip this step. 

To remove the faucet body, use an adjustable wrench to unscrew the faucet at the base. In some cases, the faucet body will simply twist off. 

You should now have access to the O Rings. 

Remove the O Rings

Use a flat head screwdriver or an adjustable wrench to remove the valve stem. Most should easily screw out within a few minutes. If you’ve installed one using silicone, take the time to remove it before forcing the valve stem out of the fittings. 

Remove the washers. Then, use a flat head screwdriver to gently pry the O-Rings out of their slots. Keeping the rings intact at this stage makes it easier to buy new ones. However, if you can’t do this, getting them off takes priority over keeping them intact. 

Buy New O Rings 

Take your O rings and washers to a store. Preferably, you can go to a plumbing store, where washers and O-rings are sold specifically for plumbing. This will mean higher quality materials, designed to resist high PSI from water pressure. If you don’t have a local plumbing store, your local hardware store will do. Make sure you look in the plumbing section for the O Rings. 

Buy the same size and density as you currently have. 

Put Everything Back Together

Fit your O Rings back onto the valve stem, put the washers back on, and then put everything back together. You may want to reapply silicone or PTFE tape to ensure a watertight fit. PTFE tape is almost always preferable, because it is easily removable. 

You can also take this time to inspect the rest of the mechanism for damage. 

Test the Faucet

Once you’ve put your faucet back together, go ahead and turn it on to see if it still leaks. Hopefully, this has resolved your issue and you now have a leak-free faucet. 

Replacing a Leaky Bathtub Valve Stem in 5 Easy Steps 

If your valve stem is still giving you issues, you might want to simply replace it. Luckily, that’s almost as easy as replacing your O-Rings. In fact, you have to do most of the steps to replace the valve stem when replacing the O Rings. You’re all set. Once again, make sure you have the water to the bathroom turned off before you start this process. 

Remove Handles/Valves 

Remove the plastic cap from the handles and unscrew them. Pull them free from the valves. Then, set the screws and handles aside in a bag or tray. 

Remove Escutcheon Plate 

Remove the escutcheon plate from the wall. This should simply pull off. However, some people install them with silicone, in which case you might want to pry with a scraper, flathead screwdriver, or even a butterknife. 

Unscrew the Valve Stem

Assess your valve stem and unscrew it from the fitting. In most cases, you can do this with an adjustable wrench. In other cases, you’ll have to loosen a screw on the top of the valve first. Then, pull the valve stem out of the fitting. 

If there are two valve stems, repeat the process for both handles. 

Buy a New Valve Stem

Take your valve stem to a plumbing outlet and purchase a replacement in the same size. Make sure that the fitting type is the same. For example, threaded valve stems are the most common. However, you might also have a splined or square broach end. Make sure the fitting matches. When in doubt, it’s always an option to ask someone at the store for assistance. 

Put Everything Back Together 

Put your faucet back together in reverse order. You may want to use PTFE tape or silicone to ensure that everything fits snugly together. 

Frequently Asked Questions 

Doing your own plumbing can be intimidating. Plus, leaking faucets are frustrating. You likely still have questions. Hopefully this FAQ helps. 

Do faucet stems wear out? 

Yes. Faucet cartridges or valve stems experience constant wear and tear every time you turn the water on and off. The valve stem runs between the handle and the valve body. It functions to rotate the valve on and off. Over time, this stem can wear down, degrade, and become corroded. It’s also normally easy to tell when that happens. For example, if your shower faucet is less sensitive to turning the knob than it used to be. Or, if your faucet leaks. If your faucet handle slips when turning the knob, it’s also highly likely to be a stem issue. 

Why does my tub faucet leak when the shower is on? 

Your faucet most likely leaks because of a poor shutoff in the valve. This can relate to the valve stem or cartridge, to how the handles are set up and tightened, and to the valve body itself. For example, if you have a faulty diverter installed, it could result in a leaking faucet. The best option is to take the faucet apart to look for damage or problems. 

How much does it cost to fix a leaking bathtub faucet?

In most cases, you can replace an entire leaking bathroom faucet for as little as $25 for a budget model. However, most problems are even cheaper to fix. For example, replacing O rings won’t cost more than a few dollars and gas to the store. If you have a leaking valve stem, it’s likely less than $5 to replace. Of course, you will need two of them in most cases, but it’s still relatively cheap. 

Can you change a shower cartridge with the water on? 

No. You’ll have to turn your water off to replace the shower cartridge. 

Final Words 

If you’re having problems with a leaky bathroom faucet, you can spot fix and attempt to diagnose the issue. If you want a sure fix, replacing the entire faucet is normally easy and cheap as well. However, most faucet leaks come from the valve stem or the O rings, so replacing one or both should resolve the issue.

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