We don’t usually replace our old shower or faucet cartridge unless it’s become clogged or worn out. Even so, it’s a rare case to see people changing cartridges every once in a few years. This actually means that cartridges last for years and a new cartridge would keep up your shower or faucet’s performance for more than a decade.
If so, then you might wonder why you’re facing low water pressure after replacing the cartridge of a water outlet. It mainly happens when there’s lots of debris stored on the aerator while replacing the old cartridge. Along with that, there’s a possibility that you’ve installed an incompatible cartridge model.
Whatever the reason is, you can’t ignore the fact that low water pressure can’t help you at all. Thus, we’re thinking of telling you how to solve the low water pressure issue after replacing your old cartridge.
Possible Reasons & Solutions For Low Water Pressure After Replacing Cartridge [Quick Overview]
Before getting to the detailed troubleshooting guide, let’s have a short glimpse at the quick table below, summarizing all the potential reasons for this issue with their recommended fix:
| Probable Reasons | Recommended Fix |
| Partially closed water shut-off valve | > Head to the water shut-off valve for your bathroom fixtures and open it all the way |
| Improper installation of the cartridge | > Inspect the cartridge for loose connection and tighten it. > Make sure the cartridge is properly aligned within the shower valve. |
| Handle not adjusted correctly | > Take off the handle and adjust the anti-scald valve to the right position |
| Debris clogging outlet | > Inspect the shower cartridge for any clogs. > Check for broken parts lodges within the faucet. > If so, remove the clogged debris and sediments. |
| Incompatible shower cartridge | > Examine your newly installed shower cartridge whether it is right fitted for your shower model. > If not, you will need to replace it. |
| Bad shower cartridge | > Replace the worn-out shower cartridge |
Why Is There Low Water Pressure After Replacing Cartridge [Easy Solutions]
Less or no water after replacing shower cartridge indicates that you must’ve missed a few things while installing a new cartridge. It’s not that much of a big deal if you know how to overcome the flaws.
So, let’s see which things reduce the water pressure in your bathroom and how you can solve them.
1. Water Shut-off Valve Not Opened Properly
If you are struggling with the low water pressure in your shower and faucet, the best possibility is you have closed the main supply valve or the bathroom’s mother valve while installing an OEM cartridge. Even it is a common mistake for users not to open the main water shut-off valve for bathroom fixtures after completing plumbing works.
If really that happens, you won’t get the required pressure from the shower or faucet.
How To Fix:
So as for the first step, you will need to check and verify whether the main valve is opened like before or not. If not, open it all the way. If required, use a wrench to move the handle and increase the water pressure.
After doing that, you can also see the hot and cold water inlets behind the outlet valve. The balancing spools of these inlets should be in the same position and turned on completely.
Now check for water pressure!!!
2. Cartridge Not Installed Well
A common thing we all know is the cartridge handles the water temperature and pressure regulation. That’s why a cartridge not installed properly should provide less water pressure especially if it’s not installed lubed or the O-ring is not set properly.
Because a rough cartridge’s full body can’t go inside the housing. Any portion of the white plastic body below the O-ring remaining outside means the cartridge is still not installed. And loose O-rings end up leaking water. Which also lets air go inside and block water.
How To Fix:
In this step, you will need to inspect your newly installed cartridge to ensure proper installation. Start by removing the shower handle, and cover plate and get access to the shower valve assembly where the cartridge is installed.
When the cartridge is revealed, put it off and see how rough the surface is. If needed, add some plumber lube or WD-40 to make the cartridge’s outer surface smoother.
When done, a lubed cartridge would easily go inside the valve’s housing. When it fits properly inside, place the O-ring carefully without keeping any gaps.
[Note: The O-ring shouldn’t be loose. It is better to replace the old O-ring rubber along with the old cartridge]
3. Handle Not Adjusted Properly
The user’s command to a shower or faucet comes to the cartridge through the handle. When the handle or knob can’t turn accordingly, the pressure regulation won’t happen at all.
Especially if the anti-scald device or the limiter is set for narrow movement, the handle fails to move completely to a side. This causes the outlet to pour less water with minimal pressure.
How To Fix:
First off, make sure you have turned off the water supply to your shower. Now, take off the handle using an Allen wrench. There’s a white round thing over the cartridge called an anti-scald device. Slowly pull it off a bit. Twist the device both leftwards and rightwards and adjust the position of the device.
When done, push the limiter back and reinstall the handle back to the right place
4. Debris Clogging Outlet
Now, if all of those three reasons aren’t the real issue in your case, consider debris and mineral deposits blocking the water gateway.
While replacing the old cartridge, a few amounts of debris and other wastes might’ve been stored in the aerator or the faucet body. These wastes block a big area of the shower or faucet and limit the water flow for good.
How To Fix:
Use a wrench to pull off the aerator from the mouth of the faucet or showerhead. Take a toothbrush and rub the inside of the aerator roughly. You can also use a water and vinegar solution as a solvent to wipe out deposits.
There might be debris inside the outlet body too. For that, bring out the main body of the shower and use the “Snaking” method.
The snaking uses a semi-hard wire with a piece of nylon cloth wrapped on top. Then, push the nylon head inside through the body pipe. While doing so, twist the wire as much as you can. The friction inside would break the hard deposits quite easily.
Then, put everything back and turn on the valve in full mode. Keep things in this way for a while. The water flow would clean the whole outlet and bring back the usual shower cartridge water pressure.
5. Incompatible New Cartridge
There’s a huge possibility that you’ve bought an incompatible cartridge model to replace the old one. Most of the cartridges and their brands aren’t interchangeable. That’s why, when you buy one without checking the requirements of the valve, you face problems like no water, hot water pressure low all of a sudden, etc.
How To Fix:
- Carefully uninstall the new cartridge from the system. Take the cartridge and its packaging to the seller and ask for a replacement.
- Normally the seller won’t agree to refund you unless the sale is a sole mistake of the store. So, you need to start thinking of buying a compatible model.
[Note: You can’t find suitable cartridges for 20/30 years’ older valves. In that case, try having a universal cartridge for your shower or sink.]
6. Bad Shower Cartridge
In most cases, a defective shower cartridge is the culprit itself for why you are not getting adequate water pressure after replacing the cartridge. Though it is uncommon for a newly installed shower cartridge, it can be possible! Yes, you got it right!
I’ve even faced the same situation in my recent plumbing work in my bathroom fixtures.
The cartridge can be defective due to manufacturing flaws, shipping and handling issues or simply wear and tear out over time.
Let’s get the details below:
Can A Bad Shower Cartridge Cause Low Water Pressure?
Yes, definitely! A bad shower cartridge can cause low water pressure in your shower. This mainly happens due to clogged sediments in the cartridge or an internal damaged component that restricts the normal water flow to your shower.
A shower cartridge is an essential plumbing device installed in the shower valve that is designed to regulate the water flow to the entire shower system. Most of the shower cartridges also control the water temperature coming out of the shower head through a special temperature mechanism.
However, over time, cartridges can become defective due to clogged sediment or hard mineral buildup. In the case of a newly installed shower cartridge, the best chances are the internal components like seals, O-rings, or gaskets can wear out or be damaged due to mishandling of the faucets.
If your shower cartridge isn’t functioning well or has gone bad at all, nothing but you will need to replace it with a new one. For convenience, check out the comprehensive guide to explore how you will deal with a malfunctioning shower cartridge.
Why Is There No Hot/Cold Water In Shower After Replacing Cartridge?
As with low water pressure, it is also a common issue users most often face that there is temperature fluctuation in the water even after installing a new cartridge. Either you would have no hot water or no cold water in this instance.
Several factors contribute to the fact That you’ve no hot water from your newly installed the new cartridge. Such as:
| Reasons | How To Fix |
| The hot side and cold side of shower valve are reversed | > Switch the hoses back in the right positions. |
| Partially closed hot water inlet | > Open the water shut-off valve all the way |
| The non-return valve isn’t installed correctly | > Inspect the non-return valve to see whether it is in the right direction |
| Airlock in the shower | > Bleed air from the water supply line |
| Stuck balancing pool | > Replace the balancing spool if required |
| Incompatible cartridge model | > Ensure you are using a compatible cartridge for your shower model. |
In case you have no cold water in your shower after replacing the cartridge, double-check you have adjusted the temperature correctly. If needed, turn the RSL in the direction of the cold water. Also, check for airlock or blockage in the cold water supply pipes. In most cases, you may need to replace the bad pressure balancing valve or the cartridge as a whole.
FAQs:
Does the cartridge affect water pressure?
As we said before, a cartridge can have a huge impact on the water pressure. The small part works accordingly to set your comfortable water flow speed staying right behind the handle. So, a clogged cartridge can lower your shower’s water flow.
Why is my water pressure low after replacing the faucet?
If your new faucet’s water pressure is now, there should be any leakage or blockage in the faucet system along with the piping.
Why does my shower leak after replacing the cartridge?
If your shower faucet leaks after replacing the cartridge, be sure the cartridge isn’t installed correctly or you’ve used an incompatible replacement part for your shower model. At times, high water pressure, and loose or broken cartridge seals can cause this issue.
What causes no hot water after installing my new faucet?
If there is no hot water after replacing a new faucet, check for an airlock in the faucet. Inspect the faucet aerator screen for any clogs and clean it. Clean the blockage in the plumbing pipes as well and repair leaks if there are any.
Why is there low water pressure in the shower after replacing the valve?
Low water pressure in the shower after replacing the valve can be attributed to several reasons. Such as if the new valve isn’t adjusted correctly or due to installing the wrong-sized valve. Plus, clogged plumbing lines, faulty pressure regulators or trapped air in the water lines cause this issue.
Do new kitchen faucets have flow restrictors?
Every faucet model from the early 2000s has an aerator. It restricts the maximum water flow by letting the water go through different patterns. Mainly, aerators are known as water flow restrictors.
How do you fix a slow-flowing kitchen faucet?
The first thing you need to do is clean up the aerator and cartridge. Then, try to replace the worn-out parts as quickly as possible. After that, your kitchen faucet should be back to normal again.
Final Thoughts
Basically, you need to remember two things first; choose the right type of cartridge and take all the necessary preparations to replace the old cartridge. By doing so, you can erase the possibility of all the major reasons causing low water pressure in your faucet.
Last, but not least, try to use the water softener with your lines to make hard water okay to use. Otherwise, you can face something even worse than low water pressure. So, we wish you all the best. Reach us if you want to know anything more.
About James
James founded HomeUpgradeLab & was sharing his experiences to fix issues related to bathroom and toilet fixtures & fittings. Read to know more about James Hill & how he started this blog.