Why Is the Water in My Water Heater Cold?

Aug 03, 2023, 12:28pm

There are different types of water heaters: electric, thermodynamic or solar water heaters. These models have a specific way of generating the necessary energy and supplying a house with hot water.

Some breakdowns can occur on water heaters: low water flow, a leak or even a temperature problem. When you notice a temperature failure and the water is cold, then you will need:

  • test the thermostat
  • drain the water heater
  • test resistance

Most households rely heavily on their water heaters for daily tasks, such as showering, washing dishes, and doing laundry. So, if you turn on your faucet and cold water comes out when you’re expecting hot water, it can be a significant inconvenience. Several reasons could explain why the water in your water heater is cold, which we will discuss in this article.

Why Is the Water in My Water Heater Cold?

1. Faulty Thermostat

One of the first potential causes of cold water is a faulty thermostat. The thermostat’s role in a water heater is to regulate the temperature of the water in the tank. If it malfunctions, it may not adequately heat the water or may not heat it at all.

2. Tripped Circuit Breaker

If you’re using an electric water heater, the problem could lie with your circuit breaker. If the breaker tied to your water heater has tripped, the electricity necessary to heat the water will not reach the unit. Check your circuit breaker box to ensure that the switch associated with your water heater is in the ‘on’ position.

3. Faulty Heating Elements

Both electric and gas water heaters use heating elements to heat the water. In electric units, these are typically rod-shaped elements, while gas water heaters use a burner and heat exchanger system. If these components are faulty or burned out, the water won’t heat up. A professional can test these elements and replace them if necessary.

4. Sediment Build-up

Over time, minerals present in water, such as calcium and lime, can accumulate at the bottom of the water heater tank. This build-up forms a barrier between the water and the heating element, which can prevent the water from heating up efficiently. Flushing the tank can often solve this problem.

5. Size of the Water Heater

If your water heater is too small for your household’s needs, you may consistently run out of hot water. This issue is particularly prevalent in households with peak usage times, such as in the morning when everyone is showering. Upgrading to a larger unit or a tankless water heater that provides on-demand hot water can solve this problem.

6. Damaged Dip Tube

A dip tube carries cold water from the top of the tank to the bottom for heating. If this tube is broken or damaged, cold water may not reach the heating element and could mix with the heated water, leading to a lower overall temperature.

Why Is the Water in My Water Heater Cold?


A resistor is a part that is inside the tank. In particular, it allows you to convert electrical energy into heat, convert electricity into heat to heat the tank. You can have armored resistance, which is immediately visible when the block is removed, and soapstone resistance, which is inside the shell.

To check if your resistance is working, you must disassemble the tank and drain it.

  • If you have an armored resistor: set the multimeter to continuous mode, unplug and remove the thermostat, then place the multimeter’s leads on the resistor’s terminals.
  • If you have a soapstone resistor, place the test leads on the metal of the resistor.

If the multimeter shows 1 or OL, then the resistance is faulty and will have to be changed.


While these are the most common issues, numerous other problems could cause your water heater to produce cold water. Some of these fixes are simple, while others require professional expertise. If you can’t diagnose or fix the problem yourself, it’s time to call a plumber or a water heater repair specialist to ensure your access to hot water is quickly restored.