Water Heater Repair Basics

Unless you’re a very handy person, it’s generally best to leave water heater repair to the professionals. It involves handling water and electricity, which can be dangerous.

Before contacting a plumber, turn off your water heater’s power supply find the breaker in your service panel, and switch it off. Call Plunger Plumber immediately if you can’t get it fixed.   

water heater repair


The thermostat is a device that controls the temperature of your water. Most water heaters are built with two heating elements and associated thermostats. A faulty upper thermostat could lead to lukewarm or even cold water in the house. In addition, the thermostat is responsible for signaling the lower heating element to come on. The most common problem with a water heater is the heating element going out, but that can often be fixed by flushing it periodically.

Changing a thermostat is very simple, but it should always be done with the power to the water heater turned off. It is also important to use a new thermostat that is the same as the old one to ensure proper operation.

First, you will need to turn the breaker off for your electric water heater. Then you will need to remove the insulation and plastic protective cover from the access panel. Once you have removed these coverings, you will need to turn the breaker back on and move any insulation or debris that is blocking the breaker from making contact with the power wires.

Once you have the breaker back on, you will need to use a digital multimeter to test for continuity in the thermostats. This is accomplished by touching one of the meters leads to the reset terminal on the top of the thermostat and the other leads to the left-side thermostat terminal (the one with the power wires attached). The meter display should show close to zero Ohms of resistance if there is continuity in both the upper and lower thermostats.

If the thermostats are both showing continuity, then you may need to replace your water heater element. You can do this by turning the breaker off for your water heater and then removing the access panel and insulation. You will then be able to unscrew the old element and set up the new one. Once the new element is in place, you will need to slide each side of the thermostat bracket downward into place and lock it into place.


Many homeowners don’t give their water heater much thought until it stops working. That’s when their hot showers become lukewarm, they can’t do laundry or wash dishes, and their quality of life takes a nosedive. At that point, it’s time to call a plumber for a water heater repair.

There are several clues that your water heater is a bad egg, including:

Constant lukewarm showers are indicative of a lower heating element that’s failing. This might be due to rust and sediment build-up or could be a sign that the upper heating element is going out.

When you notice this issue, it’s important to shut off the power to your heater by switching the breaker in your service panel to the “Off” position. Then, remove the access panels, insulation, and plastic safety guards from each heating element to reveal their exposed wires. Using a non-contact voltage tester, test each wire to make sure it is not live before you touch it. Depending on your results, you might need to replace one or both of your elements.

If your water heater isn’t producing hot water at all, the problem might be as simple as a tripped limit switch or a broken thermostat. If the problem is deeper, however, you might need to drain your tank to clean out accumulated sediment.

Your gas water heater’s thermocouple and gas control valve are another set of components that may require attention. The thermocouple senses whether the pilot light is lit and then releases the gas to heat your water. The gas control valve, on the other hand, is what turns off your water heater if there’s an overflow of the tank.

A gas water heater typically has two thermocouples. Replacing a thermocouple costs about $150 while replacing both can cost up to $300.

Dip Tube

A dip tube is a piece of plastic pipe inserted into the cold water inlet of your water heater tank. It helps keep cold water from mixing with hot water as it goes to the house, which is most important for gas and electric water heaters. It also keeps cold water from settling too far down in the tank, which can clog the burner or cause low pressure in the house. It is only used in tank-type water heaters, not tankless systems.

Normally, your dip tube lasts for as long as your tank, but it can degrade over time. The wear and tear of use, changing water temperatures, and the acidity of the water can shorten the life of your dip tube. If you find pieces of white plastic in your faucet strainers or shower heads, it is a sure sign that the dip tube is disintegrating.

The good news is that it’s not difficult to replace your dip tube. First, shut off the water supply valve to your water heater, then remove the old tube from its inlet nipple. If you’re not confident in your ability to do this safely, contact a plumber for help.

Once you have removed the old dip tube, clean out the inlet nipple and put a new one in. If possible, use a cross-linked polyethylene (PEX) tube, which will last longer than a standard vinyl or copper tube and is more resistant to water temperature changes. A PEX tube can also be curved or have openings to create turbulent flow and reduce sediment buildup.

Finally, attach the new dip tube to the inlet nipple and connect it to the water supply line. Turn the water back on and check for leaks. If you have no problems, restore power to your water heater and enjoy the hot showers you’ve been missing! These steps are a great example of the many plumbing repairs that can be done at home with minimal DIY knowledge. If you are not comfortable working on a gas or electric water heater, it’s always a good idea to call a professional plumber for help.

Pressure Valve

The water heater’s pressure valve is a safety device that opens to release excess pressure from the tank. It’s typically welded onto the top of the tank and attached to an upward-pointing discharge tube. If this valve goes bad, you’ll have a hot mess to deal with – water and steam will gush from the tube until the pressure is relieved. A leaking pressure valve means you’ve got too much pressure in your water heater, and it needs to be replaced immediately.

In addition to leaking, you should also watch out for excessive noise or debris in the water coming from the tube. This could be a sign of rust in the water heater tank, which requires a professional inspection and repair.

You can test your water heater’s temperature and pressure relief valve at home by removing the discharge tube (the hose connected to it). Make sure to shut off the dialers on the water heater (for cold water and gas) and attach a hose to the outlet at the bottom of the tank. Drain the water into a bucket and then, using a pipe wrench, open the T&P valve slowly and partially. When you feel the water flow from the discharge pipe begin to slow down, stop and close the valve.

While it’s best to have a professional do the actual replacement of the valve, you can do the testing yourself by wearing gloves and goggles. After putting on your gear, place a bucket underneath the discharge tube and then very gently and partially open the valve again. If the lever snaps back into place, you have a working relief valve. If the lever stays down or the water continues to pour, you have a stuck valve and should call a plumber to replace it. Performing this test twice each year can help catch problems before they become dangerous. The water heater is one of the most expensive appliances in your home, so it pays to take good care of it! By testing and maintaining your water heater’s components, you can ensure it lasts a long time without needing to be replaced.