Water Heater Maintenance: Tank vs Tankless

Let’s face it – we need our water heaters. Whether it’s for those nice warm showers or sparkling clean dishes, most of us have our water heater working double time on a daily basis. It follows then that regular maintenance is essential for keeping your water heater running efficiently, preventing costly breakdowns, extending its lifespan, and ensuring a consistent supply of hot water. While you can certainly hire a professional to carry out periodic water heater maintenance procedures, it’s actually a very manageable process to do on your own.

Of course, both tank and tankless water heaters benefit from proactive maintenance. But due to their contrasting designs and components, their maintenance routines do differ in certain ways. Let’s discuss!

Tank Water Heaters

These are the most common type of water heater. They can either be gas powered or electric, and (as their name implies) store a large amount of water in a tank. After continual use overtime, sediment can begin to settle at the bottom of the tank causing decreased efficiency and higher energy bills. And corrosive elements in the water can attack the metal components within the tank leading to potential leaks and damage. That is why giving your heater a little TLC seasonally is so important.

Electric Water Heater

Gas Water Heater

Tankless Water Heaters

Contrary to tank-style, these devices heat water “on demand.” When hot water is needed, water is channeled through the heater, it is heated to a designated temperature, then off it goes to your desired location (check out the diagram below). You don’t have to worry about sediment buildup in a water tank (because there is no tank), but you do have to worry about potential mineral buildup throughout the piping and heating chamber.

Standard Water Heater Maintenance

Although tank and tankless heaters have their distinct differences, some fundamental maintenance steps apply to both:

Visual Inspection – Let’s start with the easy (and somewhat obvious) items. It’s advisable to simply check in on your water heater on a regular basis. This means giving it a visual inspection to ensure that there are no defects or leaks. If you have an older gas water heater, you can check to make sure that pilot light is ignited and burning steadily. However, most newer water heaters no longer have standing pilot lights, instead using an electronic igniter.

Be sure to look at the the combustion air intake and flue to make sure there is no damage or obstructions. Also pay attention for any strange noises or odors. And don’t forget to keep your heater and the area around it clean!

Test The Temperature – Take a look at the temperature on your water heater’s thermostat. Then, using a water or kitchen thermometer, test the max temperature coming out of your faucet. Make sure it correlates with the thermostat setting. *Note that the normally acceptable temperature range is 115ºF to 130ºF. Temperatures over 130ºF can present a scalding hazard. This picture below shows a water temp that is way too hot!

Check the TPR Valve – The Temperature Pressure Release (TPR) Valve is designed to release water if the temperature or pressure in a water tank exceeds safe levels. Without a pressure release function, the pressure can buildup inside the appliance and lead to damage, and in worst cases, a water heater explosion. So needless to say, you definitely want this thing working properly! This mechanism should be tested annually.

To test it, place a bucket under the discharge pipe and lift the valve’s tab to release some water. If water flows freely and stops when you release the tab, the valve is working correctly. If you lift the tab and no water comes out or it continues to run once closed, the valve needs to be replaced.

Now that we’ve established the related maintenance items between the two heater types, let’s examine the differences.

Before we move on, please note that in the following sections, we touch on some more advanced maintenance. These steps can normally be performed by a qualified plumbing specialist. However, if you are comfortable with more advanced DIY maintenance tasks, you may consider doing these steps on your own!

Advanced Tank Water Heater Maintenance

As we discussed above, the main defining factor of the tank-style heater is that it stores large amounts of water, and its maintenance focuses on managing sediment buildup and protecting the tank from corrosion. So how do we do that?

Anode Rod Inspection and Replacement – The sacrificial anode rod (usually made of zinc) is crucial for preventing the tank’s metal parts from corroding due to water acidity, alkalinity and bacteria. The rod attracts corrosive elements, which causes it to deteriorate, instead of the tank itself. This rod should be removed and inspected annually. Before removing it, you should first shut off the power or gas. You should also shut off the supply lines leading to and going from your water heater. 

If the rod is less than a half inch thick or has excessive mineral buildup, it should be replaced. When re-inserting the rod into the water heater, make sure to apply pipe joint compound or wrap plumber’s tape around the threads to ensure a secure seal.

Flushing the Tank and Removing Sediment – It is recommended to flush your water heater once a year, in order to mitigate the excessive buildup of sediment. Again, don’t forget to shut off the power supply or gas, and cut the water supply. In order to drain the tank, you must connect a hose to the drain valve at the bottom of the tank.

You can drain the water into a bucket or a nearby floor drain, if available. Once empty, close the drain valve, add a gallon of vinegar, and let it sit for several hours. Afterward, fill the tank back up with water, and subsequently drain the water/vinegar mixture out of the tank.

Finally, once the tank is completely flushed, you can seal up the drain valve and fill the tank back up. Make sure you turn on a faucet in the house so that any excessive air pockets can escape the tank and water lines.

For a more in depth look at anode rod maintenance and performing a tank water heater flush, check out this informative video!

Advanced Tankless Water Heater Maintenance

As stated above, tankless-style water heaters with not have the issues that come along with stored water. Their primary maintenance focus is on preventing and removing mineral scale buildup within the heating chamber and pipes.

Descaling and Flushing the System – Tap water contains minerals like calcium and magnesium that can build up on and erode the walls inside the water heater, blocking water flow and decreasing efficiency. Therefore, it is recommended to flush your appliance at least once a year (maybe even every 6 months if your water supply is significantly hard).

We can’t say it enough – make sure to cut off the gas or power before flushing out your system! You should also close the water lines to and from the heater before servicing. Next you will want to connect a hose to each service valve (shown above). The hose attached to the “cold water in” line should connect to a submersible pump in a bucket, and the hose attached to the “hot water out” line should be emptying into the same bucket.

Add about 3 gallons of descaling solution or white vinegar to the bucket, then turn on the pump to circulate it through the appliance. This process should continue for 30 minutes to an hour. When the flush is complete, seal up the service valves, open the supply valves, and turn the power or gas back on.

Cleaning Water and Air Filters – Most tankless units will have water and/or air intake filters, as well. These should be inspected and cleaned or replaced every 6 months.

For more info, check out this great tutorial on how to flush your tankless water heater system.

Inspecting Water Heaters

Water heaters are one of the big ticket items we look at during our standard home inspections. Our inspectors understand the importance of these systems, and give them the thorough evaluations they deserve.

First of all, we are going to conduct a visual inspection. Any signs of damage or leaking will certainly be noted. The inspector will check for any apparent corrosion, and whether or not a TPR valve is present with a properly sized discharge pipe.

We also want to know if the water is being properly heated. The inspector will test the max temperature of the water from a faucet inside the house, making sure it correlates with the settings on the water heater thermostat. If there are noticeable issues that aren’t apparent from a visible inspection, the inspector will recommend further evaluation from a plumbing specialist.

Our inspectors also want to make sure the environment around the heater is safe and free of any harmful fumes. So they use specialized tools to check for gas leaks at the gas supply lines. They also to make sure the exhaust is exiting the living space properly through the flue by testing for carbon monoxide (as shown below).

Are You In Need of a Home Inspection?

If you are closing on a home in the Colorado Front Range, we hope that you will consider Scott Home Services for your home inspection services! Feel free to visit us online to learn more or contact us to schedule your inspection services today!