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Why Do My Drains Smell So Bad?


If a nasty stink is emanating from your drains, you’re not alone. It’s a common problem. But, what’s the cause?

It could just be bacteria or a clog, or it could be something more serious like a sewer gas leak. When you smell something off coming from your drains, do some sleuth work to root out the source.

Here are some of the most common reasons your drain might cause you to plug your nose. Some have simple DIY solutions. Others require a professional plumber.

Top Causes of Bad-Smelling Drains

  1. Bacteria Buildup

The smell could be coming from something as simple as bacteria and gunk buildup. Think about everything that goes down you drains, including food, hair, and dirt. When those items get stuck in the pipes, a smell can follow. Smells often accompany blockages, so it’s a good sign that it’s time to clear your pipes.

Clearing your pipes will hopefully get rid of the smell (and slow drains). Contact the drain cleaning experts at HELP to ensure your drains are cleaned properly. We have been providing drain cleaning services for over 80 years to Cincinnati communities as well as Northern Kentucky and Southern Indiana residents.

  1. Dry P-Trap

If your drain hasn’t been used recently, then you might just need to run the water and refill the P-trap to get rid of the smell. Drain lines have a goose-necked section of pipe installed to block sewer gas from wafting up through the drain. When the sink isn’t used, the water in the trap evaporates. This empty drain causes the smell and allows the gas to come into your home.

To prevent P-traps from drying out, run a little water in each of your faucets once a month.

  1. Clogged or Missing Vent Pipes 

You may or may not know that your drain pipes are connected to a network of vent pipes, which brings fresh air in and allows wastewater gas and odor to escape. Together with the drains, this is known as the drain-waste-vent (DWV) system. Usually these vertical vent pipes exit through the roof, away from windows and other vents.

If clogs develop in the main stack, a number of issues can develop, including smelly drains. You may be lacking vent pipes, so speak with a professional plumber about getting one installed.

  1. Stink from the Sump

If you smell something funky coming form your basement sump pump, you may be directing wastewater into your sump pump instead of through the main sewer drain line. Sometimes, homeowners will direct water from the washing machine into the sump pump, which can collect in the sump pump and cause a bad smell.

By reducing the amount of pipes that drain into your sump pump, you can reduce the smell. Make sure you have a proper-fitting cap over the top to help keep smells from wafting into your home. It will also keep objects from falling and collecting inside.

  1. Grease

If grease or fat gets stuck in your kitchen sink drain, a rotten egg or mold smell can ensue when it congeals. It is important to never pour grease down your drain. Throw 2 teaspoons of baking soda into the drain, followed by vinegar and chased with a pot of boiling water. This solution will eat away at the gunk, while the water will wash it away. 

  1. Garbage Disposal

Food scraps left to rot in the kitchen garbage disposal will cause a stink. A moldy or rotten smell is the sign that you need to clean the garbage out of the disposal. Run cold water over the disposal while you run it for about 30 seconds. Running ice cubes through the disposal can help clear the food, and throwing in some lemon or lime slices in will create a citrusy smell that will quickly mask the previous rot.

  1. Drain Trap

Having a proper drain trap installed in your new sink or bathtub is a must to prevent sewer smell from making its way into your home. Without it, there’s nothing to block the smell from coming up into your home. A professional needs to install the drain trap.

Does the Water Smell?

Water issues like sulfates can cause a smell. If sulfate-reducing bacteria get into the hot water heater, a rotten egg smell is the result.

If you suspect the smell is coming from the water itself, contact a professional plumber to assess your water pipes and water quality.

DIY Drain Cleaning and Deodorizing

Don’t wait until your drains are clogged and smelly to do something about it. Here are some pro tips for maintaining clean and free-flowing drains:

  • Pour about ½ cup of baking soda and ¼ cup of salt over the drain.
  • Then, start pouring a big bottle of household white vinegar.
  • You should see foam and bubbles rise from the chemical reaction.
  • Let everything sit for about 15 minutes.
  • Then rinse everything with just-below-boiling water.
  • Finally, let the cold tap run and rinse everything away.

If water freely flows down the drain, great! If not, try the process one more time before calling a professional plumber. Do this every few weeks to help prevent smells and blockages. Other tips include keeping hair out of the drain and avoiding chemical drain cleaners, which can harm your plumbing system.

Keep your garbage disposal clean and fresh by periodically putting some ice and lemon/lime wedges in the disposal. Learn more drain cleaning and garbage disposal tips.

Do You Smell a Sewer Odor?

Bad-smelling drains can indicate a problem with the main sewer line.

If the methods above don’t stop the smell, or if you’ve noticed multiple drains with sewer odors, then the issue is likely damage to the sewer line. The sewer line removes the waste water from your home and transports it to the city sewer system (or septic tank). If the sewer line becomes blocked or sustains damage from corrosion, tree roots, ground shifting, or construction, it will start to back up sewage into your pipes and eventually into your drains.

This needs immediate action or sewage will start to seep into the basement and cause severe damage to your foundation. Sewer line repairs or replacements require a professional plumber.

The experts at HELP will use cameras to locate the break or blockage and then make targeted repairs. In many cases, we can use trenchless drain repair technology to fix main sewer lines without having to dig up your property.

Drain Cleaning Service in Cincinnati

Professional plumbers may use industrial water jetters, snake augers, and pipe camera equipment to find and fix the cause of your drain smell. An experienced plumber can remove the clog at its source so you can enjoy a clear drain again.

HELP Plumbing, Heating, Cooling and Drains is the company to call for this type of detailed plumbing repair in Cincinnati, as well as Northern Kentucky, and Southern Indiana. We back our work with a 100% money-back guarantee.

Call (513) 333-4357 today to get any drain cleared for only $97.

Posted in: Plumbing

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