Hot Water Pressure Low but Cold Fine [Causes and How to Fix]

Imagine being in this scenario. You are about to shower, but it is still cold when you turn the water on. You tried turning on the hot water just by itself, and it flows, but it is very weak. Are you wondering about the reasons behind it? Why could it possibly cause hot water pressure low but cold water fine?

If your home’s cold water seems normal, but your hot water is not that strong, focus on the water heater. Check the shut-off valve first. Make sure to open it up completely. If the shut-off valve seems fine, the next most likely culprit is sediment buildup in the water heater.

Read on to learn more about the causes of hot water pressure low, but cold is fine and how to fix them.

Why Is Your Hot Water Pressure Low but Cold Fine?

Hot Water Pressure Low but Cold Fine

There are several causes why your house’s hot water supply does not seem like it is flowing as it should. Before calling your regular plumber or fixing the problem yourself, which is not advisable, let’s tackle these probable causes first.

Here are some of the common culprits that you should keep an eye out for:

1. Debris and Sediment

First, compare the flow rate of your hot water and cold water. If just the hot water has problems, you might need to flush out the hot water tank. The reason might be that too much scale and sediments have collected inside the tank.

If your hot water tank is quite old, the chances are that the insides have rusted quite a bit already. It could be why there are blockages in your hot water lines, thereby reducing the water pressure.

2. Blocked Showerhead and Taps

Is the hot water pressure only weak in the upstairs bathroom? Is it fine when you test the kitchen faucet? If the low water pressure is only in one area of the house, the fixtures might be at fault. There might be a blockage in the showerhead itself.

Fortunately, this is an easy fix that you can do yourself. Likely, the tap is just worn out. This is more than likely to happen if you live in a rather old house. In that case, you could either replace the tap washers, which is pretty simple, or replace the entire thing.

3. Leaking Pipes

Another probable reason for not much hot water pressure is a leak in hot water pipes somewhere. To figure out if this is the problem, shut off every faucet and shower in the house. After that, check your water meter. If it is still spinning, you can be sure that there is a leak.

It could be that the hot water tank itself has sprung a leak. There may also be a leak somewhere in the hot water piping system in your home. Whatever the case may be, it is best to get the assistance of a professional plumber. The reason is that the leak might get quite serious because it is already affecting the water pressure.

You should have this problem looked into as soon as possible to prevent excessive water damage. In worse cases, it could cause the water to get in contact with your house’s electrical wiring.

4. Blocked Hot Water Heater Filter

Some hot water tanks come with filters at both the inlet and outlet. Over time, these filters have collected so much debris that they get blocked. Turn off the water main and check if the filters in your hot water system are still good. If not, you need to clean them. You may also have them replaced if they already have too much damage. Both these tasks are simple enough that you can do them yourself.

5. Faulty Tempering Valve

The tempering valve makes sure that the water in the hot water tank does not get too hot. However, like other moving and removable parts in your water heater, it can get damaged or faulty. In that case, you will have to replace them. Thankfully, tempering valves are easy to find, and they do not cost that much.

6. Blocked Hot Water Pipes

If you live in a rather old house, pipe blockages may be the reason why your hot water is not flowing as strong as it should. Now, unlike some of the other fixes mentioned in this list, you will need the help of a professional plumber.

Have a professional plumber look into this issue to ensure the appropriate fixing of the problem. Note that unclogging hot water pipes requires a professional’s help. Remember that it is not as simple as inserting a plumber’s snake into a drain and fishing out the blockage.

7. Faulty Installation

Did you have your hot water tank installed only recently? If so, the people who sold you the water heater might not have done an excellent job at installing it. The installers might have put too many bends. They may have also used mismatched pipe diameters. The only way to make sure about it is to call the people who sold you your hot water tank. Have them fix it for you since it will surely still be under warranty.

8. Hot Water Heater Needs Replacement

Hot water tanks can’t last forever. The reason why you are not getting enough water pressure could be that it is already on its last legs. If you already had your heater repaired more than once last year, it is probably time to replace it.

Having it fixed now, only to break down again after a couple of months, is not very practical. However, if you want to replace the water tank, ask your plumber what they do in your shoes.

Again, hot water pressure is low but cold fine – what causes this issue? If the hot water pressure is low but cold fine, you should check your faucets for sediment and limescale buildup. If you experience this problem only in the shower, then check the shower for damage.

No Hot Water in Apartment

Problems Caused by Low Hot Water Pressure

hot water pressure low but cold fine in shower

Low hot water pressure is not usually something severe and destructive. This is unless you ignore the problem for a long time. Meanwhile, if the water pressure is too high, it can cause a lot of serious damages to your plumbing system.

With that said, low water pressure can still cause problems. Here are some of them:

1. Difficulty Cleaning

Getting enough hot water from your tap can cause problems, especially with cleaning tasks. For instance, washing dirty dishes and doing your laundry will be more difficult than they should be. The reason is that you will not have enough hot water. It makes it quite hard to wash away the dirt and soap off the things you are trying to clean.

2. Appliances Reliant on Hot Water Will Not Be Efficient

Your washing machine and dishwasher can’t clean as efficiently as they used to if there is no hot water. Some devices may even get seriously damaged if they do not have enough hot water to work with.

3. Can Signify a More Serious Issue

What if the low hot water pressure is not the problem but rather a symptom of the real problem? The low hot water pressure might mean a leaking pipe somewhere in your plumbing. Leaking water can be very destructive. This is especially true if you did not do anything about it for an extended period.

Broken or leaking pipes can cause serious flooding and water damage. Standing water can also trigger hazardous mold and mildew growth and proliferation.

4. High Mineral Content in the Water Can Be Dangerous

Your hot water may not get enough pressure because the pipes and water tank are covered in mineral scales. If that is the case, it may cause the water to taste a bit funky. Having some minerals in your drinking water is beneficial.

However, too much mineral content over a long period can cause all sorts of health issues. Some of the health issues from excessive mineral consumption include heart problems, kidney issues, and neural disorders.

Why Do I Not Have Hot Water After Turning Water Back on?

Can You Replace the Hot Water Heater Yourself?

why is my hot water pressure low but cold fine

Secure a Permit

Secure a permit from your local city hall if you want your current hot water tank replaced. Note that building codes often change as new technologies develop. That said, the installation process has to adhere to all the requirements set in your locality.

Also, rethink installing the heater on your own to avoid spending a lot. Remember that many things could go wrong by installing the heater incorrectly. There are even some scenarios that would result in you losing your house.

Prevent Accidents by Hiring a Professional

For instance, you are installing it, then forget to include a T&P valve. There is a chance for a catastrophic failure to occur in that scenario. Many people got into an accident due to an exploding water heater. You do not want to add to that statistic, do you? A certified professional must install your hot water tank to prevent untoward incidents.

What Are the Permits You Have to Secure for Water Heater Replacement?

If you want to save money, it is advisable to get the permits for replacing the water heater yourself. This will allow you to shave a bit off the top of the costs. The only thing to do is visit your local building permits department. After that, you should pay a couple of dollars for the permit. You can find the building permits department in the city hall complex.

Aside from the building permit, it is also necessary to get a couple more permits, namely:

1. Electrical Permit

Get an electrical permit because you will be making electrical modifications to your house to accommodate the new heater. This is especially true if the circuit breaker and fuses are too small. The small size may cause challenges in handling the water heater tank.

2. Plumbing Permit

Secure this permit if you want to modify your house’s plumbing for your new heater. This is also necessary when you want to add a new gas line or extend the plumbing. The reason is that you need to relocate the hot water tank somewhere else in the house.

Conclusion – Hot Water Pressure Low but Cold Fine

Have you noticed that your house’s hot water pressure is not as strong as it used to be, but the cold water still seems fine? You should first focus on the hot water tank in that scenario. Is the shut-off valve fully opened?

The other reason why the water pressure is low is excessive sediment buildup. It could be that the sediment accumulated in the tank or scaling in the pipes.

Having low hot water pressure might not seem like a big deal. However, it might just be a symptom of a bigger problem that you are not aware of. If the hot water pressure does not improve after a day or two, get the services of a professional plumber. This is the key to getting to the bottom of the problem and having it fixed.

Related reading:

Hot Water Heater Is Only Lukewarm [Causes and How to Fix]

Hot Water Not Working but Cold Is [How to Fix]

Does Hot Water Shrink Clothes? Washing Clothes in Hot vs Cold Water