A tub spout leaking from the back is one of those issues that may appear marginal at first, but it could result in a pretty big problem if you don’t attend to it soon enough.
On top of being a potentially serious infrastructural issue, it is also extremely annoying.
While it may start as a small issue, a leaky tub spout could eventually affect your water pressure.
In this detailed guide, we will explain the most common causes and solutions for this problem, which will not only help you fix it but also prevent it in the future.
Why is your tub spout leaking from the back?
With any household issue, it is necessary to find the source of the problem to be able to fix it permanently.
While a leaky tub spout usually isn’t too complex of an issue, it may take some time to detect the cause.
However, our list of common causes should make this step a lot easier for you.
1. Faulty seat washer
The seat washer, also referred to as the seating washer, is located inside the faucet and its main role is controlling and releasing the water (opening and closing) whenever you turn the water on or off.
You can only imagine how many times a day the seat washer needs to open or close.
Therefore, it is safe to say that the seat washer rightfully goes through some wear and tear that can lead to leaks.
Due to the constant movement when opening and closing on a daily basis, the friction damages the seat washer, making it stiff.
It is also possible for the rim of the seat washer to erode.
All of these factors affect the quality and stability of the seat washer and over time, it can loosen up.
It is necessary for the seat washer to be positioned tightly inside the faucet to prevent the tub spout from leaking.
2. Damaged or rusty faucet stem parts
Aside from the seat washer, which seems to be the number one cause of tub spout leaking, other faucet stem parts could also be causing this problem, whether they’re clogged, damaged or broken.
The faucet stem elements, including the packing washer, bonnet washer, packing nut and bonnet, are all prone to wear and tear over time, as well as corrosion and physical damage.
3. Tub spout diverter
In case the tub spout is leaking from the back when you’re using the shower, it could be that the problem is the diverter on your tub spout.
The role of the diverter is basically to direct the water flow from the water spout to the showerhead.
However, all the tub spout elements, including the tub faucet and the shower diverter, are prone to mineral buildup and clogging, which affects their functioning.
If the tub spout diverter is clogged or blocked in any way, you won’t be able to completely shut off the water flow completely when you’re done showering.
This problem will cause the water to leak not only from the back of the tub spout but from the showerhead, as well.
4. Old or malfunctioning tub spout
One of the possibilities, especially if you haven’t changed your tub faucet in a long time, is that it may be time to invest in a new one.
Sometimes, even if you were to replace all the elements individually, nothing but replacing the tub spout altogether can help.
How to fix a tub spout leaking from the back
A leaky bathtub faucet is luckily one of those issues that usually doesn’t require professional help, especially if you were able to detect the issue yourself.
Whether you need to clean the tub spout structure or the problem is in a single element, the process shouldn’t be too long or complicated as long as you’re following our step-by-step guide.
1. Clean the tub spout elements
The first method of fixing your leaky bathtub faucet is inspecting all the elements closely and removing all the gunk and mineral buildup that accumulated inside it.
This process will also give you the chance to take a closer look at the elements and replace any broken or damaged components to ensure that the leaking stops once and for all.
The first step would be to remove the tub spout by unscrewing it from the wall.
The process may vary depending on the model, but this is usually done by turning the spout counterclockwise until it comes off.
Once you remove the spout from the wall, it is time to inspect all the visible elements, including the O-ring and the tub spout diverter, which usually looks like a small plastic plate.
In case there’s a substantial mineral buildup on the elements, which is usually the case, you want to submerge them in calcium, lime and rust remover solution (1:1 water to CLR ratio).
Submerging the tub spout in this solution will allow for the accumulated mineral buildup to dissolve completely without damaging the valve body.
In case you have no CLR, white vinegar could also work, too.
You want to let the tub spout sit in this solution for at least 15 minutes, then take an old toothbrush and scrub the elements to get all the mineral buildup off.
We also recommend wearing gloves to protect your skin.
After cleaning the tub spout thoroughly, make sure to rinse it to get any excess product and gunk off.
All that is left for you to do is reinstall the tub spout and check if the leaking has stopped.
In case this method hasn’t worked, it is possible that the spout is damaged and needs to be replaced.
2. Replace your tub spout seat washer
Once you’ve removed the tub spout from the wall and opened it to inspect the parts, you may notice that some of the elements, such as the seat washer, are damaged or corroded.
If this is the case, you can easily replace these components with new ones.
However, in case the majority of the structure is damaged and worn out, keep in mind that it is far more practical to replace the tub spout altogether.
Using a small pocket knife, disassemble your faucet handle and shut off the water supply to this faucet to be able to safely remove it.
You will also need to open the valves to release any excess water before you remove the handle of the faucet.
Using a screwdriver, remove the handle screw and simply pull the handle off the wall.
In case the handle is stuck due to buildup, you may need to apply more force or apply heat (using a hairdryer) to loosen it up.
While more force may be needed to remove the handle, you still want to be careful as you don’t want to break it.
You could also use a handle puller tool specifically made to remove the handle safely.
Once you’ve removed the handle, it is time to unscrew both the stem assembly and the escutcheon using a bath socket wrench.
In case the stem assembly is stuck, you may need to apply some penetrating lubricant.
As we’ve mentioned, a damaged seat washer is usually the main issue and the reason behind a leaky tub spout.
All you need to do to remove it is press it in the center and then turn it counterclockwise until it snaps off.
In case it is stuck or has any mineral buildup around it, you may also need to apply some penetrating lubricant to be able to remove it.
Coat the new seat washer with a thin layer of pipe dope and then secure it in place using a seat wrench.
Paul Wilson is a highly skilled plumber with over ten years of experience in the industry. He holds an IDPH license and takes pride in his ability to tackle many plumbing issues and successfully complete even the most challenging projects.
