Why Does My Hot Water Smell Bad?

12 Apr 2021

When you open the hot tap, you expect to receive a stream of clean, pure, hot water. In most cases, that’s exactly what happens. However, in some situations, you may find that the water coming out of that tap smells a little “off”. If your hot water smells like rotten eggs, there’s an issue that needs to be addressed. What is it and what should you do? We’ll explore that and more below.

What’s the Issue with Smelly Hot Water?

If your hot water is smelling more and more like rotten eggs, then chances are good you’ve got a bacterial infestation on your hands. Sulphate bacteria (sulphur-producing bacterial organisms) can get into your water heater and wreak havoc. This is particularly true in certain situations. However, it could be due to another problem, such as contamination within the water supply.

Check the Cold Tap

The first thing you need to do is close the hot tap and open the cold tap. Give the water a minute to run, and then smell it. If the smell is still there, then the issue is outside your home and with your water supply – either your well or the municipal supply to your home. If you open the cold tap and the water smells just fine, then the issue is your water heater.

What’s Happening?

In an ordinary situation, your water heater runs long enough and gets hot enough to kill off the bacteria that enter. All water contains some level of bacteria, even fully treated municipal water. However, if your water heater isn’t set to a high enough temperature, or it has been off for some time, such as while you were on holiday, or during a prolonged power outage, then those bacteria have a chance to grow and reproduce.

Another Possibility

While the most common cause of smelly hot water is bacterial contamination, there is another possibility. If your aging water heater has a magnesium anode, it can react with the sodium in soft water to create sulphur gas. In most cases, this only happens if you have hard water and have installed a water softener in your home.

The magnesium in the anode reacts with the sodium in the water. The result is sulphur gas. The tell-tale sign that this is the cause will be a combination of smelly water and gas flowing out when you open the hot tap. So, if you hear sputtering and hissing combined with a broken water stream from the tap, this is likely the issue.

How to Remove Smelly Hot Water

So, how do you remedy the situation of bacterial infestation in your water heater? Water treatment may be able to help. However, in some cases, you may need to replace the cylinder itself, this is particularly true if the unit is already close to its end of life.

Categories