Have you ever experienced it? You are having a nice warm shower on a cold morning all of a sudden the water gets so cold. It’s a situation that you would never want to experience again. If this happens regularly, you need to find out why hot water runs out fast and find a remedy. Below are some of the reasons why your water heater runs out of hot water fast.

Hot Water Runs Out Fast: Common Reasons

It is not enough to worry you if your water heater only ran out of hot water once. However, if the situation occurs repeatedly, you might need a solution to it. Look at some of the reasons below and their fixes.
Hot Water Runs Out Fast
Your Water Heater Needs Replacing

A water heater needs replacement after ten years. Though some water heaters last for up to 13 years, the efficiency of the water heater starts diminishing after the eighth year. Some water heaters have a manufacturer date printed on the label, but some don’t. If yours doesn’t have a manufacturer date and the water heater runs out of hot water fast, use the serial number to ask the manufacturer when the heater was made.

In a typical serial number, the first two digits represent the month, and the digits in the third and fourth positions indicate the year of manufacture.

What to do About It

An older unit is less efficient. If your hot water heater runs out fast and it has been operational for more than eight years, consider replacing it. This will not only ensure you never get cold showers, but it will also save energy in your home.

Thermostat Problem

When the hot water heater runs out of hot water too fast, the thermostat might have a problem. Irrespective of the fuel your heater uses, whether gas or electricity, you need to reset your water heater thermostat and see if you will get enough water when you need it. You should also raise the temperature settings on the thermostat to see if the thermostat tells the heater to heat water at a low temperature.

What to do About It

If, after changing the settings on the thermostat, the water heater runs out of hot water fast, you might need to schedule with the local plumbing service to have the thermostat tested and replaced if found faulty.

You Need a Bigger Water Heater

Perhaps the reason why your hot water heater runs out fast is that you have a small tank. If there are several people in your family, the hot water tank might be small for your family’s needs. If you do a lot of hot water washing or there are people in your family who use hot water for a hobby, you might need a bigger tank.
You Need a Bigger Water Heater
Again, you might be using a tankless hot water heater that is not adequately sized to supply enough hot water for your family. If your how water heater runs out of hot water fast and you use a tankless water heater, you might need to get a heater with a tank to store enough hot water.

What to do About It

Once you have established that you need a bigger water heater to avoid a water heater that runs of hot water fast, you will first need to determine your family’s hot water needs. First off, establish the peak-hour hot water demand.

The peak-hour is the time that most water is used in the house. In most families, this might be between 6:30 am, and 7:30 am when most family members are getting ready for work.

According to the U.S Department of Energy, one person uses 10 gallons of shower water for one shower – multiply this by the number of people who shower during peak hour then add any other hot water used for cleaning.
After the estimate, you will need to pick a water heater tank with a First Hour Rating, FHR, that falls within one or two gallons of your peak-hour demand.

Debris Has Built Up in Your Water Heater

Minerals present in water might get deposited at the bottom of the tank after heating, building a layer of sediment. Again, dirt and debris in water might accumulate in your water heater, diminishing its efficiency.
Debris Has Built Up in Your Water Heater
When debris builds up in your water heater, it might clog fuel supply pipes reducing the heating efficiency. Again, sediment might build up to displace hot water in your tank. For instance, a hot water tank that carries 40 gallons will only be able to carry 27 gallons of sediment occupies 15 gallons.

One of the visible signs that your water heater has sediment and debris is when you see debris or sediment in the water that comes out of the heater. Again, if your tank is in excellent condition, but hot water runs out too fast, the problem might be debris buildup. Besides a hot water heater than runs out fast, you might hear some noises coming from your unit as an indication that debris and sediment have built up in your unit.

What to do About It

It is easy to correct this issue as all you need to do is flush your water heater. This means emptying the tank and cleaning it thoroughly with clean water. To do this, follow the water heater manufacturer’s instructions. While at it, ensure that the power supply or gas taps are switched off.

Call American Home Water and Air if Your Hot Water Runs Out Too Fast in Phoenix, AZ

Call American Home Water and Air if Your Hot Water Runs Out Too Fast in Phoenix, AZ
When your hot water heater runs out of hot water too fast, you need to diagnose and correct the issues. While doing so, you need to observe safety precautions to ensure that you do not cause more problems to the hot water system and yourself.

If your hot water runs out fast in Phoenix, Arizona area, visit American Home Water and Air at the address below:

American Home Water & Air

22047 N Black Canyon Hwy
Phoenix, AZ 85027
United States
(602) 993-0083


If your hot water heater runs out fast, you need to consider the following factors:

  • How many people are in your household?
  • How old is your heater?
  • What type of heater do you have?
  • Do you run appliances that need hot water simultaneously?
  • Could there be leaks in your hot water heater system?