How to Get Rid of Black Gunk in Sink Drains

Inspect the Mold Infestation

1. Put on protective gear. Before you start cleaning the mold, inspect the infested area. Make sure you wear rubber gloves before you handle any objects in the area. Most mold is not toxic, but large areas of black mold could be toxic and should be removed by a trained professional. Toxic mold is usually greenish black in color and is a major health risk. You should also be wearing enough clothing so that mold spores don’t come in contact with your skin.

2. Inspect the infested area. Remove all items from underneath the sink and inspect the moldy area. Throw away any mold infested items by placing them into a plastic bag and then sealing up the bag.

3. Compare your mold findings. You can compare the mold you find with pictures on the Internet to determine if it is a toxic strain or not. If pictures aren’t enough to identify the strain, you can also get a mold testing kit to make sure. If you have determined that you can clean the infestation yourself, then proceed with the following steps.

Fix the problem at its source

The best way to kill any kind of mold is start from its roots. Killing it from the bottom up will ensure that it can’t grow back. Easy and effective products that can kill black mold at the root level include baking soda and bleach. There are also stronger substances out there, but be mindful, as the chemicals used to kill the black mold can be more dangerous than the mold itself.


Preventing Mold With Dehumidifiers

A sink pipe and drain are common areas for mold to spread because of the intensive moisture. Dehumidifiers are an excellent technique to remove excess moisture from your indoor spaces.

If you utilize these devices on a daily basis, you’ll reduce your chances of getting a significant mold problem. They can be used in a variety of locations, such as the basement, kitchen, and bathroom.

Removing Black Mold From Under Sink

1. Gather Protective Gear

Don’t blunder into this project without protective gear. This kind of infestation is dangerous to your health even from far away. Scrubbing it off inches from your face is even worse.

You’ll want to gather:

  • Rubber gloves
  • Ventilated mask
  • Detergent
  • Bleach
  • Bucket
  • Bristle sponge
  • Box fans

Make sure to wear the rubber gloves the entire time you clean, and keep the ventilated mask on even after you finish scrubbing.

2. Clear the Area

2. Clear the Area

This substance thrives in moisture, so if you’ve got a crop of black mold sprouting up, you’ve definitely got a source of excess water.

We’ll talk more about locating and dealing with sources of moisture further on, but during the cleaning process, try and identify where the water was that caused this whole mess. There’s no use painstakingly scrubbing and disinfecting if the stuff is just going to come back.

After you’ve located the leak, remove all the contents from the affected room. Do this whether or not the mold has spread to them. They’ll just provide the spores with more opportunities for growth.

3. Scrub Off the Mold

You have to find the right combination of delicacy and aggressiveness for the cleaning portion. You want to scrub as hard as you can to eradicate every spore.

Be careful not to scrub in a sloppy way that flings spores and other clumps of mold here and there. Don’t give the infestation any more room to grow.

4. Disinfect Everything

Once you’ve scrubbed away the infestation, disinfect everything in the room. Nothing short of everything will do when it comes to mold. It spreads that quickly and that invisibly.

5. Air the Room Out

Aeration is an integral part of the cleaning process. Open windows, doors, and try to create a cross breeze. Bring in box fans and oscillating standing fans to increase airflow. Mold thrives in dank darkness, so make the affected room as light and open as you can.

Maintaining The Drainage System

Maintaining the drain by treating it with a vinegar/baking soda “volcano” on a regular basis is a smart technique to keep it clean. For maintenance, reduce the portions of each component by half.

A similar mold-killing cleaner can be made by mixing borax, vinegar, and hydrogen peroxide, which will froth when mixed with water. 

Step #1. Sprinkle some baking soda straight in the drain and then leave it for an hour or two. 

Step #2. Flush with hot water to kill mold and deodorize. 

Enzyme-based drain cleaners are effective in killing mold, but they frequently evaporate before they have a chance to do so.

The best mold cleaners

Let’s compare a few cleaners and see what what we can come up with.

The RMR 141 Mold Killer

This cleaner does the job of a hundred cleaners. It promises to 99.9% of household and odor causing bacteria. It covers a wide range of bacteria and surfaces, making this cleaner a mold killing multi tool. It’s safe for any facility, including schools, due to its formula that contains no abrasive chemicals.

The Puracy Organic Homecare Set

If I could pick one word to describe this product, it would be “natural”, which is exactly the message Puracy wants to get across to consumers. In this set are five different cleaning products, each with “Natural” printed across the bottles. This of course implies that Puracy only uses natural and organic products to create quality cleaning products, because natural is obviously an effective selling point. What’s better than a natural bathroom, kitchen or sink.

The Forcefield ScumBlaster Bundle

This product boasts a kit that comes with enough industrial strength cleaning chemicals to fill five spray bottles and to prove it, it also gives you a spray bottle and a measuring cup. You’ll have everything you need to tackle the black demon in your kitchen, bathroom, drains, sink, and even under places you would never expect to find it.

The RMR 86 Mildew Stain Remover

RMR is back on the list with a product that took thousands of hours to develop by their cleaning experts. The name speaks for itself. It can remove mildew stains on or under any surface with great efficiency. Long gone are the days of scraping stains and blasting them with dry ice. This affordable cleaner will rid your kitchen, bathroom, sink, drains, and any surface in your home of black mold and mildew.

Congratulations! You are informed about the dangers of the black fungus. Now you can keep your house clean. Everything from your kitchen to your sink, your bathroom to your drains, and everything under and over can now be properly protected with the cleaning product of your choice.


White distilled vinegar is an affordable, natural solution to removing black mold. Its antibacterial acidic characteristics are exactly what you need to get the job done.

Pour the undiluted vinegar into a spray bottle to apply to the area, or just go for it and pour that vinegar right onto the mold stains. Use a disposable towel and wipe away the mold from the area. If that doesn’t work, grab an old toothbrush and go to town on the problem zone. Allow time for this to dry, and then use a damp towel to wipe the area clean one more time.

How to keep mold from returning

No matter how diligent you are about removing visible mold, if you don’t address the underlying issue, it will come back. “Where there’s mold, there’s moisture,” says Larry Zarker, CEO of the Building Performance Institute, which trains and certifies professionals who specialize in creating healthy, safe and efficient homes. Here are some common mold hangouts in homes, along with ways to eliminate their moisture source.

  • Basements: Make sure gutters are channeling water away from the house. Plug cracks in foundation walls with an epoxy injection system or bring in a pro for the repair. Install a sump pump to clear water in the event of flooding or heavy rain. Put in a dehumidifier to remove moisture in the air.
  • Bathrooms: Keep the room ventilated by cracking a window, especially after showering. If you have an exhaust fan, run it while showering then leave it on for at least twenty minutes after; also leave the door ajar. Periodically check for leaks under the sink, as well as a spongy floor, which could be a sign of leaky toilet, shower stall or bathtub. Clean shower grout lines regularly with a specialized grout cleaner designed for the task.
  • Ceilings and Walls: Leaky roofs are the common culprit here. Check for missing shingles or failed flashing around openings in the roof, like at a chimney or dormer. Inspect siding for cracks or openings, including where vents and plumbing lines enter the house.
  • Kitchens: Regularly crack a window for ventilation. If you have a range hood, run it while cooking and then for twenty minutes after to ventilate steam, along with smoke and cooking fumes. Check under the sink for leaks. Inspect the seal around your refrigerator; if there’s sign of mold, air is likely escaping, so you’ll need to replace the gasket.
  • Windowsills: Seal any cracks around the window where rain is entering with caulk. If condensation is forming on the windows, and they’re double-pane, you might be able replace the glass panel to stop the moisture. But it might be necessary to replace the entire unit.

Dan DiClerico, Good Housekeeping Institute Director, Home Improvement & Outdoor Dan DiClerico has written about home improvement for more than 20 years, including countless how-to articles and reviews of products ranging from appliances to smart home technology.

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at