Why is my hot water getting colder?

Author: Beryl Schmitt  |  Last update: Tuesday, April 29, 2025

An electric water heater typically has two heating elements - one to heat the water coming in from the pipes and another to maintain the temperature in the water tank. Both of these can break, which will result in colder water. Hard water or sediment in the water can also inhibit the heating element's functionality.

Why has my hot water temperature dropped?

Over time, sediment can build up in the bottom of the tank, where the burner usually is. This can lead to slower heating or poor efficiency in your water heater, meaning lukewarm water rather than hot water. The solution for this is to drain the tank and to use a water softener.

Why does my hot water suddenly go cold?

Problems may arise within the heating exchange system or be due to incorrect pressure levels, while in other cases, a malfunctioning thermostat or issues with flow rates could account for the unexpected temperature drops.

Why is my hot water suddenly less hot?

Inspect the thermostat, which controls hot water heater temperature. If someone has recently changed the setting, that could be the reason behind your lukewarm water woes. However, if the temperature setting is correct, the thermostat itself might be broken. You can have the thermostat replaced fairly inexpensively.

Why does hot water get colder over time?

Over time, minerals in water can settle at the bottom of your water heater's tank. This sediment buildup affects the heating efficiency of the tank, forcing it to use more energy to heat the water.

Why is hot water coming out of the cold side?

How to fix a shower going hot and cold?

How do you fix a fluctuating shower temperature? Addressing a fluctuating shower temperature requires inspecting the heat exchanger, checking for any blockages, and ensuring the boiler pressure is at the correct level. It may also involve cleaning or replacing the filters if they are faulty.

How to fix sediment buildup in a water heater?

Removing Sediment from a Water Heater
  1. Flush the unit. This will prevent sediment from building up inside the water heater. ...
  2. Perform a vinegar soak. ...
  3. Keep it at the right temperature. ...
  4. Install a water softener. ...
  5. Call a professional plumber.

What are the symptoms of a bad thermostat on a hot water heater?

Signs Your Water Heater Thermostat Is Faulty
  • You have no hot water.
  • You're running out of hot water quickly.
  • The water is too hot.
  • It takes a long time for your water heater to heat the water.
  • You keep having to reset the high-temperature limit switch.

How often should I flush my water heater?

Most homeowners should flush their water heaters every 6 months or so, but if you have extremely hard water, you may want to do it more often. Flushing your hot water heater could be necessary as often as every few months depending on the mineral content of your local water supply.

Why is my shower not as hot as usual?

Common Reasons Your Shower Isn't Getting Hot

Malfunctioning water heater: A malfunctioning water heater is one of the most common reasons. If your unit is not functioning properly, it can result in lukewarm or even cold showers. Sediment build-up in water heater: Sediment build-up is another common culprit.

Why is my hot water suddenly lukewarm?

Sediment Build-Up

Now, if your new hot water heater is only lukewarm, then it may not have been used enough yet for sediment build-up—but if the unit isn't new, sediment build-up is the most common cause.

What does it mean when the hot water is cold?

If you're only getting ice-cold water from your faucets, showers and sinks, there could be a few causes. Likely, the heating elements inside your water heater are broken or not working properly—or, potentially, your thermostat is incorrectly set.

How to check a hot water heater?

But before you call the repair plumber, go through these steps to determine if the water heater is truly at fault.
  1. Check your circuit breaker. ...
  2. Check the high-temperature limit. ...
  3. Check that the thermostat is set to an appropriate temperature. ...
  4. If you have a gas-powered water heater, be sure to also check the pilot light.

Why is my water not staying hot?

A lack of hot water can be caused by a variety of issues. In electric water heaters, a power loss or heating element failure can cause water to no longer heat in the tank. In gas water heaters, a faulty gas connection, a bad pilot light, or a bad burner can cause no water to heat.

Why does my hot water go cold then hot again?

A tap or shower that keeps switching between hot and cold water could be a sign that the heat exchanger inside a combi boiler is blocked. Sludge and sediment buildup is fairly common in older boilers, especially when the filters are old. This blockage will then cause water to run hot and cold intermittently.

Why does hot water lose temperature?

Sometimes, the issue isn't with the water heater but with the distance between the heater and your faucet. Long distances, especially in colder months, cause water to cool down as it travels through uninsulated pipes. Solution: Insulate your pipes to reduce heat loss.

How do I know if my water heater needs to be flushed?

Keep an eye out for debris suddenly showing up in your water. If you notice sediment or any brown sludge coming out of your faucet, that's probably an indication that it's time for a water heater flush. If you see any of these signs, it's a good indication that your water heater needs maintenance.

Can I flush my water heater myself?

You can flush your water heater yourself if it's done on a regular basis. This guide will take you through the steps to drain and flush a gas or electric water heater. Learning how to clean a water heater is an essential part of maintaining your plumbing system.

Is it better to flush or drain your water heater?

It is recommended that you flush your water heater at least once per year. Doing so will help to prevent the potential problems that sediment can bring over time. Typically, it takes one to two hours to flush a water heater. The size of your tank will impact the amount of time it takes to drain.

What are signs your water heater is going bad?

Water heaters show several signs of going bad, including lack of hot water, temperature fluctuations, decreased water pressure, strange noises, rotten egg smell, visible leaks, rusty or discolored water, and increased energy bills. If your water heater is over 10 years old, it may be time to consider a replacement.

How do you check the thermostat on a water heater?

Put one probe from the multimeter on the reset terminal (beside the reset button) and the other probe on the left side terminal, which will be the one with power wires. If the multimeter's reading says 1, then the water heater thermostat most likely needs to be replaced. If it reads 0, it is functioning normally.

How much does it cost to replace a hot water heater thermostat?

Thermostat Replacement

Each heating element has its thermostat; if those don't work, the elements won't either. Hiring a pro to replace a thermostat averages around $150 to $200. The part itself costs up to $20 and is easily replaceable without disturbing other components if you have some DIY experience.

How to tell if your hot water heater is full of sediment?

Common signs that sediment buildup is significant include bubbling and gurgling sounds and diminished hot water when bathing, cooking, or cleaning. You may also notice water discoloration, a leaking pressure relief valve, or cracks in the tank or its connections.

How often should you flush your water heater?

Flush your water heater every six months or so. If you have harder water, or water that contains more minerals, you may want to flush it more often. If you leave town, change your water heater to its vacation setting.

How to flush sediment out of pipes?

Begin the flushing procedure by opening the hot water taps in your bathroom(s). Open ALL hot water sink fixtures, hot water bathtub or shower fixtures. Next, open all other hot water fixtures, such as in kitchens, wet bars, etc. Run all of these hot water fixtures for 15 minutes, then shut the water off.

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