17 Jan

Does Your Water Heater Backdraft?

  • Karen Mares
  • Comments Off on Does Your Water Heater Backdraft?

A backdrafting water heater is a silent hazard in your home. Most of us hear the word ‘backdraft’ and think of an early-90’s movie starring Kurt Russell, including explosions and all-consuming flames. There is another type of backdraft, however, and that’s the one we’re going to be talking about.

 First, let’s define the type of backdraft we’re discussing: 

“A current of air or water that flows backward down a chimney, pipe, etc.”

So, essentially, a water heater backdraft is when exhaust gases from an atmospherically vented water heater spill out into the room instead of leaving the house through a vent. Because the exhaust gases are high in CO2 and moisture, this can be potentially dangerous. 

This is what your water heater hood looks like:

water heater backdraft location

Does Your Water Heater Backdraft?

Here are some common signs that your water heater is backdrafting:

  1. Melted plastic at the draft hood.
  2. Corrosion at the top of the tank.
  3. Moisture at the top of the tank.
  4. Heavy condensation on the cold water pipes.
  5. Improper installation of the vent connector.


There are also ways you can visually test for backdrafting.

  1. Cup your hands around the draft hood (without touching it.) You will feel moist, warm air coming out of the draft hood.
  2. Hold a mirror up to the draft hood. It will likely fog the mirror if there is a backdraft.
  3. Place a camera with a lens near the hood. If it fogs, you have a backdrafting water heater.
  4. Cobwebs can actually be handy in this situation. If your vent hood has a few cobwebs on it, they will blow around when the water heater is backdrafting. 


What to do?

Since backdrafting can raise CO2 levels in your home, increase fire danger, and waste energy, a full inspection of your water heater is in order. We’ve discussed this essential home how-to in the past here: How To Inspect Your Water Heater.

A Casey’s Plumbing professional can also come to your home and inspect your situation, and make recommendations as to how best to fix the problem. One major culprit in a water heater backdraft is the vent piping. If the vent pipes have a bend in them or aren’t fitted for proper explusion of the draft, we can fix that relatively easily. Not all water heater problems are major and expensive!

Primary Source: Reuben Saltzman, Structure Tech Home Inspections

About Karen Mares

A Portlander born and raised, Karen lives in Southwest Portland with her husband and children. Karen has kept journals throughout her life, and she began her personal blog, Random Thoughts From A Suburban Mom in 2007. She hasn't stopped writing online since, channeling her passion for words and information into writing and communicating through social media and blogging.