Mold Smell in Washing Machine: Solved

DIY GeekMom
mold in washing machine, stop laundry mold,
The mold remedy doesn’t actually bubble. (pixabay)

I like to write about science, learning, or mindfulness. Yet here I am writing about something as mundane as a laundry problem (although I have written about laundry as a mindfulness exercise…).

My family is large and we live on a small farm, so there are lots of dirty clothes. Really dirty—I mean grease, sweat, and livestock-related odors. Our machine typically runs three times a day. You’d think with such a busy workload our washer wouldn’t have a mold problem, but it does. This is a common issue with front loading machines. I hear it’s worse in hot, humid climates.

The smell isn’t just annoying. Several of my family members have allergy and migraine problems, which mold can exacerbate. I’ve tried everything. I regularly wipe out the door seals and run it on the tub clean cycle. I run hot loads with bleach. I use eco-friendly detergents that supposedly leave no residue. I empty it promptly. I leave the machine door ajar unless it’s in use. Sometimes the smell is minor, sometimes downright awful.

Then one day I realized I didn’t have to hold my breath while emptying clean clothes from the washer. The entire laundry room smelled like, well, just another room. That mold smell had disappeared as if by magic. It doesn’t take much science to track down the variables; only one thing was different. We’d gone back to using nothing but homemade powdered detergent, something I’d used only intermittently before. This stuff is cheap and cleans well. Apparently it can also perform a mold-be-gone trick. It’s not a fluke; the smell hasn’t returned in months.

There are all sorts of recipes for homemade laundry detergent, the one listed below is what we make. Well, my husband is the one who makes it. He triples this recipe and it lasts us a few months.


Powdered Laundry Detergent


one 5.5 ounce bar: Fels-Naptha laundry soap (some recipes call for the same amount of Dr. Bronner’s Magic Soaps, Castile instead)

one cup: Arm & Hammer Super Washing Soda, sodium carbonate, not baking soda

half cup: 20 Mule Team Borax, sodium borate, not boric acid (some recipes use up to a cup)  


1. Grate soap bar into small shreds using a cheese grater, or break into chunks to shred in food processor.

2. Add washing soda and borax. Mix. You can put the ingredients in a blender or food processor if desired.

3. Store in airtight container with measuring spoon.

4. Use one to two tablespoons for regular loads, three tablespoons for heavy loads. Adding more doesn’t improve cleaning power.

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4 thoughts on “Mold Smell in Washing Machine: Solved

  1. I use this recipe with one alteration – I use Ivory instead. When I was researching, I found it was the cheapest soap with no “lotions” added.

  2. I have one of the HE machines and we have been plaqued with the oh-so-nasty odor. Is this homemade detergent suitable for these machines. We mistakingly used regular detergent in the machine until we realized we were supposed to be using the designated HE detergent – but that is when I started noticing the smell.

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