“Help! My bathroom smells like rotten eggs!” This is a relatively frequent request we get from homeowners. If you’re getting that sulfuric smell from inside your house, you likely want to know both why it’s there and whether it’s a plumbing problem that needs to be fixed quickly. In order to answer that question, we need to ask some more specific questions.

Is the smell from the water itself?

Man cleaning his washroomIf you’re telling yourself, “My sink water smells like rotten eggs,” then the next step is to test the water.

  1. Use a faucet in one room (like the kitchen) and pour water into a clean glass.
  2. Go to another room (like the bathroom) and pour another glass of water.
  3. Take both glasses outside (or to an area that doesn’t smell like your bedroom) and smell both glasses.
  4. Figure out which glasses of water smell.
    1. If both glasses smell, it’s likely your water. Move on to the next question to see if hot or cold water is affected.
    2. If one glass smells and not the other, move on to other faucets in the house and test them. Record which rooms are having the problems. This may be a result of bacteria buildup in one of the pipes or connections.
    3. If neither glass smells, the sulfuric smell may be coming from drainage problems in specific sinks.  

Is the smell coming from hot water only?

Now, it’s time to do another test. Do the glass-of-water experiment once again but with completely hot and completely cold water.

  • Hot Water Only: If it’s the hot water, your hot water heater might need to be disinfected. You’ll need to replace the anode rod and disinfect the tank. When dealing with the hot water tank, you’re going to want to make sure that the room smells like rotten eggs rather than gas before you deal with it – a gas leak can be quite dangerous! (If this is not something you’re comfortable doing, call your local handyman, like us.)
  • Cold Water Only: The pressure tank for your well could be affected. (Obviously, this is only for homes with wells.)
  • Both Hot and Cold Water: If both hot and cold water stinks, you likely have sulfuric tap water coming in. Pittsburgh locals may want to test their water for lead and other particulates as you’re dealing with sulfuric water. Some individuals like to install a filtration system that helps with this issue.

Is the smelly water only in one area of your house?

If your water smells like sulfur in one faucet but not the others, there could be a localized plumbing issue along one pipe or fixture. If there are unnecessary “dead legs” of plumbing leading nowhere and simply capped off, sometimes anaerobic bacteria can build up there, leading to stinky gas. Before connecting with your plumber, though, you’ll probably want to make sure your sink smells like rotten eggs due to the water coming in and not the drain. Double-check this with another glass-water experiment.

If the smell is coming from your drain, there could be bacteria locked in the P-trap. Try disinfecting by pouring some bleach down the drain.

Are the smells only coming from your bathroom?

But what causes a rotten egg smell in the bathroom? It could be sulfuric tap water, stinky drains or “dead legs” of plumbing, but before we start discussing how to address each part of the bathroom, let’s point something important out first:

If there’s a rotten egg smell in the bathroom, it could be a buildup of bacteria in your pipes, but if it smells like sewage, this may be indicative of more serious problems.

Often, if the sulfur smell in the bathroom is due to the quality of the tap water, you’ll often see frequent orange-and-yellow stains on the toilet bowl.

Is it your bathroom sink?

A slow-draining sink clogged with ordinary hair and soap scum can build up bacteria in the P-trap until your bathroom sink smells like rotten eggs. This smell can also happen in sinks that haven’t been used for a long time. Clear the clog by using a combination of baking soda, white vinegar and hot water. Make sure hair hasn’t clogged the drain. Connect with a plumber if you have severe clogging issues.

Is it your shower drain?

If your shower drain smells like rotten eggs, you can use the same strategy as your bathroom sink: Flush out a clogged drain with a combo of baking soda, vinegar and hot water. See if the smell improves.

Is it the toilet only?

If your toilet smells even after cleaning, considering putting a bleach tab in the tank. If the smell has a sewage scent rather than rotten eggs, it’s time to connect with your local plumber.

Is it your kitchen’s garbage disposal?

Bacteria can easily collect in your disposal, so put some ice cubes in it and safely run it to clean off the blades.

There’s a lot you can do to investigate the issue, but if this awful rotten-egg smell is persistent and the issues continue, connect with your local plumber to address it.