Make Your Tank-style Water Heater Last “Forever”
Updated: Jan 20
This works best with a new water heater, but can substantially extend the life of your existing water heater.
Ok, so nothing is “forever”. But forever can be relative – such as lasting a lifetime. And it is best if you start with a new water heater because you want to begin this maintenance when the unit is brand new in order to get it to last a lifetime. However, if you have an existing tank-style water heater, you can still extend the life of that unit by following this maintenance methodology. I will address tankless-style water heaters in a future article.
What Are We Addressing and What Do We Do About It?
The two primary issues affecting the life expectancy of your traditional tank-style water heater are:
Buildup of sediment inside the tank
Corrosion of the tank and plumbing connections
The first issue negatively impacts the efficiency and capacity of your water heater. The second issue leads to catastrophic failure of the heater, along with the damage of the associated flooding. By addressing these two primary causal factors of failure, we can extend the life of the unit.
A quick overview of how we address these issues:
Flush water heater tank annually
Replace the anode rod every five years
Water Heater Tank Sediment Build-Up
Unless you are using a water softener, the water entering your tank likely has many dissolved salts in it. The common term for this is TDS – Total Dissolved Solids. Inorganic salts and some organic matter make up the TDS. Many people refer to this as the “hardness” of the water. The higher the TDS, the harder the water. Hard water is very common here in Norther Virginia.
These dissolved salts precipitate out of solution under the heating and cooling, as well as pressure, inside your tank. By precipitate, we mean they form back into insoluble solids and create scale and sediment in your tank. You can see this in action in a coffee maker or tea kettle in use over time.
The efficiency and capacity of the water heater is reduced as this sediment builds up on the bottom and sides of your water heater. Additionally, the buildup at the bottom of a gas water heater creates a layer of insulation where the gas flames heat the water. The heater must fire for longer periods to achieve the thermostat temperature setting. This puts excess heating and stress on the metal at the bottom of your tank. In an electric water heater, the sediment may eventually cover the lower heating element and cause the element to fail prematurely. Lastly, when the buildup is severe at the bottom of a the tank, the water entrapped in this sediment is heated to the point of boiling and pockets of “air bubbles” (actually water vapor bubbles) can emerge violently out of the sediment, causing loud pops that can be quite disconcerting to hear.
For a very visual example of how much sediment can build up and what it looks like (it looks like wet sand), please check out this video:
(skip to the 0:50 mark to bypass some silliness).
Addressing the sediment problem
The basic solution is to flush the tank annually, and some even suggest doing it twice a year. I would say it all depends on the “hardness” of your water - the more TDS, the harder the water. There is a procedure to properly flush your water heater tank. But before I get into that, I need to address the concern of the tank drain valve.
Many, if not most, water heaters have a gate-type drain valve, and perhaps plastic parts – such as the knob. The problem with gate valves is twofold. They constrict the flow of water and are thus prone to blockage. They also tend to leak if the packing nut is not tight, or if the gate encounters sediment on closing. The issue with the plastic knob is that they become brittle with age and heat and can break off. Not ideal when you are actively draining 40 gallons of water.
The solution is to replace the tank drain with the proper ball valve. I strongly recommend this be done by a licensed plumber, because a plumber will install the correct fittings to prevent corrosion and leaks. A ball valve is the type that has a lever. When the lever is parallel to the pipe, water is flowing. When the lever is 90 degrees from that – i.e. perpendicular to the pipe – water is shut off. The advantages to these types of valves is that they do not constrict water flow (the inside diameter is the same as the pipe), and they are unlikely to develop a dripping leak.
There are several good videos on YouTube on how to flush your water heater tank. Here is one:
If you prefer a written step-by-step method, please see the article titled "Step-by-Step Water Heater Tank Flush".
Water Heater Corrosion
Water heater tanks come with something called an “anode”. You may even see this labeled on the top of your water heater. Technically, this is a sacrificial metal anode to protect against galvanic corrosion. If you are a boater, then you are probably already familiar with this concept. This anode sacrifices itself and corrodes so that the metal tank and fittings do not.
The anode is a long metallic rod a bit shorter than the height of the tank. Depending on a number of factors, these anode rods will last about five years. After the anode has fully sacrificed itself and is completely corroded, guess what starts to corrode next? Yup – the water heater tank and/or fittings. Again, depending on a number of factors, the water heater tank will eventually corrode through after five years or more. This is why the average life expectancy of a water heater is 10 to 12 years.
When a water heater fails in this manner, water will be coming out of the unit at the same pressure as your water supply. That is A LOT of water. Imagine tossing the end of your outside garden hose through your window into your house and turning it on for 10 minutes. Imagine doing it for 8 hours. No thank you!
Replacing your anode rod
The general rule of thumb is to replace your anode rod every five (5) years. If you begin to get a strong sulfur smell from your hot water, it may be an indication that your anode rod needs to be replaced – but do not wait for this to occur because it may or may not happen. Like the water heater drain gate valve replacement, I strongly recommend the anode rod replacement be performed by a licensed plumber. However, if you are extremely handy, you can find several good YouTube videos that show you how it is done.
I will not list the steps for this procedure as I feel a licensed plumber should complete this. If you choose to do this yourself, proceed at your own risk. Be very careful as you are dealing with potentially scalding water at pressure. The anode you remove will also be very hot. I assume no liability for a DIY job here.
One thing to note: If overhead space is limited (as it often is), there are replacement anode rods that have flexible links between shorter rod lengths that allow them to be inserted into the tank. Removing the old anode rod may have the same issue with overhead space. In this case, bending or breaking the old rod may be required. Just be very careful to make sure that if it breaks, the bottom piece does not fall back down into the water heater – you may end up buying a new water heater if it does! A replacement anode rod with space restrictions can be purchased and fitted - it looks kind of like sausage links. Incidentally, replacement anode rods run anywhere from $20 to $100.
After the anode rod is replaced, be sure to make a note of this on the side of your water heater. Using a sharpie to write “anode replaced MM/DD/YY” on the unit just makes sense for your future reference.
Nothing is forever - but with these maintenance steps, your water heater can almost be. By draining and flushing your tank annually and replacing the anode rod every five years, you can significantly extend the life of your water heater and help avoid a water heater replacement cost of $800 to $2,000. Thank you for taking the time to read this article. I hope it helps to you save some money. Feel free to contact me with any questions.
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