Close-up view of hand in white tiled shower turning the stainless steel hot water on.

Why Is Your Hot Water Running Out

Few things can be more unpleasant than being in the middle of a warm shower and suddenly feeling a blast of cold water. This unfortunate experience has happened to most of us and is a sign that you may be running out of hot water in your home.

There are various reasons why this can happen. Let’s take a look at a few steps you can take to find out why you’re running out of hot water and when it’s time to call a plumber.

Reasons for Running Out of Hot Water


Tank Size

The size of your hot water tank can play a key role in running out of hot water. If this is the case, the tank may be insufficient for your household’s needs. If you frequently run out of hot water, it could be that your tank isn’t large enough to supply enough hot water for your daily usage. On the other hand, if your tank is too small, it may be time to consider upgrading to a larger tank. Both of these factors can be a cause and a consideration on what to do next in fixing your hot water issue.

Sediment Build-up

Sediment build-up in your hot water tank can also cause problems. It is a very common problem in water heater tanks that can happen over time. The reason for this is that over time, minerals in the water can accumulate in the bottom of your tank, forming a layer of sediment that reduces the amount of hot water your tank can hold.

This buildup can also lead to your tank taking longer to heat water, which can result in a reduction in your overall hot water supply. If you have ever spent time draining your tank, you know how sediment is the last thing to address before refilling your tank and also how surprising it can be that so much sediment can build up within the tank.

Heating Element Failure

If your hot water tank has an electric heating element, it may be failing. This is more common for electric tanks since they do not have the gas option that can heat up the water sometimes quicker and also store the heated water longer.

If this is the case, you may notice a drop in the hot water supply, or the water may not get as hot as it once did. Things like how we wash dishes or how long we take showers can be evidence of seeing a decrease in the hot water supply. This would be a good example of when you’ll need a professional plumber to replace the heating element.

Thermostat Issues

If your hot water tank’s thermostat is faulty, it may cause your tank to heat water inefficiently, which can result in a reduction in your hot water supply. If you suspect your thermostat isn’t working correctly, giving a plumbing professional a call to inspect and repair it is recommended.


If there’s a leak in your hot water tank, it can definitely cause a loss of hot water. If you notice puddles of water around your tank or hear water dripping, this would be the time to give a professional a call and let them know what you have found.

Steps to Find Out Why You’re Running Out of Hot Water

Before you decide to tackle the issue yourself and before you give a plumber a call, try checking off some of the possible issues. Sometimes one issue can lead to another and having this information can help out greatly when the time comes to fix the problem.

If you do find that you are experiencing a reduction in your hot water supply, here is a recap of the steps to follow so you can help determine the cause of the problem:

1. Check the Tank Size:

Check the size of your hot water tank to ensure it is large enough to supply your household’s needs. If your tank is too small, it may be time to consider upgrading to a larger one.

2. Check for Sediment:

If you suspect sediment build-up is the issue, you can flush your hot water tank to remove the build-up. This process involves draining the tank of all water and then refilling it. It’s best to leave this task to a professional plumber to avoid damage to your hot water tank.

3. Check the Heating Element:

If your hot water tank has an electric heating element, you can check it for signs of failure. If the element is damaged or corroded, it will need to be replaced by a professional plumber.

4. Check the Thermostat:

If you suspect your thermostat is faulty, you can check it to see if it is set at the correct temperature. If it is not, adjust it and see if that solves the problem. If you are unsure how to do this or suspect that the thermostat is not working correctly, again, please call a professional plumber to inspect and repair it.

5. Check for Leaks:

Check for any leaks around your hot water tank. If you see or hear any water leaking, call a professional plumber immediately to repair the issue.

When to Call a Plumber

The question that arises the most is “When do I call a plumber?”

If you’re unable to identify the cause of your hot water problem or if you’re uncomfortable with attempting to fix an issue, then this would be the time to seek help from an expert.

If you have any reservations or are simply just unsure what to do at any step, here are three reasons to think about when it’s best to call a plumber when you’re experiencing hot water problems:

1. If you’ve gone through the steps to determine the cause of the hot water problem and still can’t figure out what’s wrong, it’s best to call a plumber. A professional plumber will have the knowledge and experience to diagnose the issue and recommend the best course of action.

2. If you notice any leaks around your hot water tank, it’s an essential place to stop and make a call to a plumber immediately. Leaks can cause damage to your home and potentially lead to more significant issues if not addressed promptly, so it is a good time to reach out for some expertise.

3. If you suspect that the heating element or thermostat is the cause of the problem, it’s best to call a plumber. Both of these components require specialized knowledge and tools to repair or replace, and attempting to fix them yourself can be dangerous and potentially cause more harm than good.

Running out of hot water is not just an inconvenience but a basic need for health and sanitary reasons. Efficiency in a properly functioning water heater affects your energy bills as well. When we think of one of the most valued and convenient needs of daily life, hot water is at the top of that list.

Please give Plumbing Doctor a call so we can help you assess the best options to maintain safety and comfort in your home and business.