Water heater not hot enough? Here’s how to fix it

Is your water heater giving you lukewarm showers instead of hot, steamy ones? If your water heater isn’t getting hot enough, there could be one of several reasons why. But you’ll be happy to know that most of these issues can be fixed with a little DIY work.

If you need any replacement parts for your appliances, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Important: The information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes, and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

Reasons why your water heater isn’t getting hot enough 

Here are some common reasons why your water heater isn’t heating along with tips to resolve the issue yourself.

The thermostat is set too low (electric models)

This is one of the easiest problems to fix in electric models. Most water heaters are set to about 120°F by default, which is fine for most homes but may feel lukewarm to some.

The fix: Take a look at the thermostat, which is typically located near the bottom. Adjust the thermostat as needed. You can turn it up to around 130-140°F for hotter water. Just don’t go too high to avoid scalding!

Sediment buildup in the tank

Sediment buildup happens when hard water deposits form at the bottom of the tank, blocking the heat from reaching the water. Over time, the heater may become less effective at maintaining the correct water temperature.

The fix: You’ll need to flush the tank. To clear out the sediment, drain the tank by attaching a garden hose to the drain valve. Then let the tank drain completely and refill it with fresh water. 

Faulty thermostat or heating elements

The upper and lower heating elements work together to keep your water hot, but if one fails, you’ll typically notice a big drop in water temperature.

The fix: LIVE VOLTAGE WARNING: For this test, the water heater needs to be plugged in and powered on. Please be very careful to protect yourself from electric shock, which has the potential to cause serious injuries. Don’t ever test live voltage if you’re uncomfortable using a multimeter. Use a multimeter to check the voltage supply of the heating elements. If one is getting 240 Volts AC but it isn’t heating, you’ll need to replace it. 

You can also check the element(s) for scale build-up after draining the water from the heater. If you find excessive build-up, then the affected element will need to be replaced. 

If the element looks good but it’s not receiving 240 Volts AC, then you’ll need to replace the thermostat.

Broken dip tube

The dip tube delivers cold water to the bottom of the tank, where it gets heated. If the dip tube is broken or damaged, cold water will mix with the hot water at the top, leaving you with warm, not hot water.

The fix: Replace the dip tube if it’s broken. To do this, you’ll need to disconnect the cold water inlet, pull out the damaged dip tube, and install a new one. 

The unit is too small

If your water heater isn’t staying hot, it might simply be too small for your household’s needs. If you’re using a lot of hot water in general or a lot all at once— such as taking multiple showers or doing laundry and running the dishwasher at the same time—then your water heater may not be able to keep up. 

The fix: Consider upgrading your water heater to a bigger model or try to space out your hot water use. You may need a larger tank or a tankless water heater to meet your hot water demand. 

If upgrading sounds daunting, you can call a professional plumber to assess your situation and recommend the right size water heater. If you’re looking for size recommendations for a combination water or space heater, such as tankless and indirect units, you’ll have to contact a qualified contractor.

Frequently asked questions

Get answers to some of the most common questions about water heaters.

Why is my water heater only warm, not hot?

This could be caused by a broken dip tube or a malfunctioning thermostat or heating element(s).

What do I do if my water heater isn’t staying hot?

You may need to flush the tank, replace the heating elements, or see if your water heater is big enough for your home’s needs.

Additional information

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