Why does my water smell like sewage?

12/09/2022 Stephen Tamlin

Key facts: 

• Your water smells of sewage due to bacteria in your drain pipe producing gases that arise when the faucet is turned on.
• Hydrogen sulfide is the gas most likely to cause this sewage smell. It is commonly caused by bacteria that forms in your hot water heater when it is run at low temperatures or turned off for a period of time.
• Hydrogen sulfide can be smelled at levels as low as .5 parts per million. At 1 PPM it will smell musty, and at 1-2 PPMs it will smell like rotten eggs.

Have you noticed your water smells of sewage?

There’s nothing worse than a foul odor coming from drinking water and it’s even worse when the smell of sewage is seeping out of your faucet. The sewage smell you’re experiencing, which may also resemble the smell of dirt or rotten eggs, could be the result of a few different factors including, but not limited to, gases in your drain caused by bacteria from food and waste, or an issue with your hot water heater.

The smell of sewage in water is usually down to a build up of bacteria found in your pipes, usually a build up of hydrogen sulfide due to your hot water heater either running at a low temperature or has been out of use for a period of time.

What Causes The Smell?

Your water may smell like sewage due to the presence of bacteria that comes from food, soap or other materials sitting in your drain. This bacteria causes a heavy gas to fill the drain near the sink and when the water is turned on the gas is forced upwards and into the air around the sink making it seem like the water itself smells.

In some instances, the smell only occurs when using hot water. If this is the case, the smell is likely originating from bacteria growing in your hot water heater. This can happen if your hot water heater temperature is too low or if it’s turned off for long periods of time, like when you go on vacation. Fortunately the bacteria in the hot water heater should not be harmful to you, but it will need to be eliminated in order to remove the smell from your tap water.

This sewage smell can also be the result of hydrogen sulfide. The presence of this gas can be toxic but more than likely it will be detected before reaching a toxic level. Humans can detect hydrogen sulfide at as low as .5 parts per million (PPM). Anything less than 1 PPM will have a musty smell and between 1-2 PPM will have a rotten egg smell.

What Should You Do?

To determine if the bad smell is coming from your pipes or from your water, fill a glass of water and walk it away from the faucet before smelling it. If it does not smell, the culprit is likely the pipes and drain. If there is bacteria inside your drain, you’ll need to disinfect the sink and pipes using a small amount of soap and a small brush to clean the pipes right inside your drain.

If your hot water heater is the issue, you can try turning your hot water heater temperature up for up to 24 hours and running the hot water taps to flush the pipes out. Remember to be vary careful and proceed with caution if you decide to turn up the temperature of the hot water heater.

If you have a well as your water source, the hydrogen sulfide may be originating there. If this is the case you may need to consider contacting your local water testing lab to have your water source tested for contaminants.

What can help reduce the smell of sewage?

The best method to remove the smell of sewage in your water as much as possible is to use shock chlorination treatments within the pipe and continue to pump out water from said pipe until the smell of chlorine has disappeared.

Drinking Cleaner Water

If your tap water smells like sewage and is the result of hydrogen sulfide gas, it is likely your water will have an odor until the culprit is uncovered and eliminated. The issue is not in your water itself but rather in the pipes and water source. If you are concerned about any other contaminants entering your drinking water, investing in a filtered water cooler is an option and Waterlogic offers a water dispenser range. Request your quote on a water cooler today.