Hot Water Tanks


Hot water tanks are a vital part of our residential plumbing systems. Almost every home has a hot water tank these days and more and more home owners are installing multiple tanks to provide them with the hot water they require. Like many plumbing systems in your home, most people take for granted just how important their hot water tank is, until something goes wrong with it. It is at that point when you truly begin to appreciate what your hot water tank does and just how essential it is to your daily life.

Given the significant role hot water tanks play in our daily living, it is surprising that most hot water tanks never have any maintenance work completed on them until there is a problem. Like anything you own, it is very important to properly and regularly maintain your hot water tank. On average, a hot water tank will last anywhere from 8-15 years. A few simple steps and a few minutes on a regular basis can save you tremendous hassle and costly repairs down the road.

First and foremost, it is very important to know where your shut off valve is for your hot water tank and also the main water shut off valve for your home. The hot water tank shut off valve turns the water off to the hot water tank but leaves the water on in the rest of your home. The main water shut off valve to your home turns the water off completely in your home and would be very important if your hot water tank shut off valve is seized and won’t turn off. Just simply knowing the location of these two valves will significantly reduce the flow of a leaking hot water tank and allow you to possibly avert a flood and damage to your home and property.

It is good practice to ensure that you regularly open and close your shut off valve to your hot water tank and main shut off valve of your home. This helps prevent them from seizing up over time, rusting and not functioning when you need them to. We recommend doing this every three months and to add a reminder to your calendar so you don’t forget. Unfortunately, poorly maintained shut off valves that don’t function properly, are an all too familiar situation encountered on a daily basis. Spending a few minutes ensuring your shut off valves are in proper working order will save you money and water damage down the road.

Also it is very important to know the manufacturer of your hot water tank and where the serial number and model number are on your tank. This is typically located on the front of the hot water tank about half way down the tank. This is called the rating plate; however, it is simply a sticker with this information on it. You should also familiarize yourself with the warranty on your hot water tank and what it covers. Failure to know this information leaves you open to unethical plumbers who won’t ask the necessary questions to determine if your hot water tank is covered under warranty, simply to make a few extra bucks.

To help ensure that your tank is operating most efficiently, you should ensure that the temperature is set to 120 Fahrenheit on the tank. This is the optimal temperature at which the tank will operate. This also helps to avoid scalding from water that is too hot coming from the tank.

Setting the temperature on your hot water tank:

  • Locate the thermostat, which is on the gas valve found at the bottom of the hot water tank.
  • Adjust the temperature by turning the dial. The thermostat will have letters not numbers to indicate the temperature. You will have to refer to your owner’s manual to determine which letter corresponds to the temperature you want to set it to.
  • To check the temperature of the water you can use a thermometer and hold it under the hot water coming from one of your fixtures closest to the hot water tank.

As part of your regular scheduled maintenance of your hot water tank you should drain and flush the tank every six months or when the manufacturer recommends. This helps to prevent sediment from building up in the tank.

Draining and flushing your hot water tank:

  • Turn down the temperature of the hot water tank.
  • Turn off the hot water tank shut off valve to ensure that there is no additional water flowing into the tank.
  • Open the hot side of a faucet that is in close proximity to the tank (ie. utility sink faucet or bathroom faucet). This allows air to get into the hot water tank in order to fully drain the tank.
  • Connect a garden hose to the drain valve located at the bottom of the tank.
  • Place the other end of the garden hose at or in your floor drain and open the drain valve on the tank. It will take approximately a half hour to drain a standard size tank.
  • While the drain valve is open, turn on the shut off valve for the tank a quarter of the way to flush water through the tank and down into the floor drain. Flush the tank for about 10 minutes and then turn off the shut off valve and continue to let the tank drain until empty.
  • To complete the process, close the drain valve and open the shut off valve to allow your tank to fill up again. Make sure you continue to have the hot side of a nearby faucet on this entire time and while the tank refills, as this will allow the air in the tank a place to go as the tank fills.
  • Once the tank is completely full you should repeat the process of draining the tank once more, without flushing the tank, in order to drain out any remaining sediment in the tank. You will know your hot water tank is full again when water starts pouring out of the open faucet nearby. At that point you can turn the faucet off.

Additionally, the T&P valve (temperature and pressure relief valve) should be opened and closed every year or when the manufacturer recommends. This helps to prevent the T&P valve from seizing up, like the shut off valves. The T&P valve is located a quarter of the way down the hot water tank from the top. It is a brass fitting and it protrudes out the side of the hot water tank. It has a silver handle on it, which you can open and close.

Another common problem homeowner’s face is low hot water pressure. This is due to sediment build up on the outlet of the hot water tank, which restricts the flow of water. This happens as the tank ages and can be easily and inexpensively rectified by calling a licenced plumber. The outlet is simply cleaned and then the problem should subside.

Most if not all hot water tanks have what is called an anode rod. This device helps prevent corrosion from taking place inside your hot water tank. It is therefore an integral part of your hot water tank and its maintenance is vital to the longevity of your hot water tank. The anode rod is located on the top of your hot water tank and sticks into the tank. It is not always marked; however, you owner’s manual should pinpoint its location. The anode rod should be changed when it is about 3/8 of an inch thick in diameter. It is roughly about an inch thick in diameter when it is brand new. The anode rod should be checked every year or when the manufacturer recommends it. Unfortunately every manufacturer makes these slightly different therefore in order to maintain or replace the anode rod, it is recommended to contact a licenced plumber/gas fitter. Keep in mind that if you have a water softener you may need to change the anode rod in the tank more frequently.


As your tank ages, it is inevitable that at some point, it will reach the end of its life. Even tanks that have had regular maintenance completed will fail at some point as they age. The most common reason a hot water tank fails is due to a leak. Simply put water is negatively charged as it enters the hot water tank. The negatively charged water looks for positively charged ions, which it takes from the tanks anode rod. As the anode rod wears out over time, the water isn’t able to obtain the positively charged ions it requires from the anode rod and starts to eat away at the inside of the hot water tank. This causes the tank to spring a leak and require replacement. Sometimes homeowners report seeing rusty coloured water coming from their hot water fixtures, this can be a sign that this process is occurring in your hot water tank and it is recommended that you call a licenced plumber. It is also good preventative practice to install a drain pan under the hot water tank to prevent excess property damage if and when it leaks. It is also advisable to place a nine volt water alarm on the floor near the hot water tank so that you are notified when and if it leaks. These are two inexpensive ways to help ensure your property and home is protected.

No one likes taking cold showers or having to boil water on the stove in order to wash dishes or bath the kids. Typically, as luck would have it, this type of problem arises at the most inconvenient time for the home owner and the most costly time of day or week, when plumbing companies are charging overtime rates. It is precisely these hassles that home owners face when their hot water tank isn’t working properly. The options at that point are to either pay the overtime rates to have a plumber come out and fix the problem or manage with cold water, or no water at all, depending on the problem, until the next business day.

In an effort to help you get you through to the next business day and keep your money in your wallet there are a few steps you can take when your tank springs a leak.

  • It is imperative with a leaking tank to slow the flow of water from the hot water tank. The first thing you should do is shut the water off to your hot water tank and open the hot side of a faucet near your tank. This will relieve pressure inside the hot water tank and considerably slow the leak.
  • In order to continue using your hot water tank over the weekend or evening, you will need to leave it in this state and only turn on the water to the tank when you are going to use it. Although this is somewhat inconvenient and requires running back and forth between the fixture you are using and the hot water tank, it will enable you to still have hot water and save you the costly overtime fees charged.

Replacing a hot water tank can be costly depending on the size of the tank and application. In an effort to save a few bucks, some homeowners will attempt to replace or repair their tank on their own. Despite this temptation, it is never advisable for a homeowner who is not a certified plumber/gas fitter to work on or replace their hot water tank. This type of work is more technical and given you are dealing with gas or electric and water you should always ensure that a certified plumber/gasfitter works on your hot water tank. There are proper tests and procedures followed in the installation of a hot water tank and failing to complete these may cause malfunction, gas or water leaks, carbon monoxide poisoning and fire/explosion to name a few. Additionally, should something happen to your home or property from work completed by an uncertified homeowner, your insurance company may not cover your loss.

Finally due to the flooding that hit Alberta in 2013 it is important for homeowner’s to know that the Air-Conditioning, Heating and Refrigeration Institute (AHRI) recommends that any flood-damaged heating and cooling equipment be replaced, not repaired. This is very important with hot water tanks as there are safety controls on the hot water tank that if submerged in water may malfunction. If you have had any sort of floor or water accumulation in your basement around your hot water tank it is advisable to hire a plumber/gas fitter to come out and inspect your hot water tank.

With regular maintenance your hot water tank should perform well and last years. A few inexpensive preventative measures will save you hassle, time and money down the road and ensure your home and belongings are as safe as possible. Hiring a qualified plumber/gas fitter when required will ensure you get the best service and expertise in dealing with your hot water tank.

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