Why Black and Brown Slime Builds Up in a Washing Machine's Detergent Drawer
Dark, slimy deposits in a washing machine's detergent compartment are caused by bacteria and fungi, not by a faulty appliance. Experts advise cleaning the compartment about once every two months and letting it dry out.
Opening the detergent compartment of a washing machine can sometimes reveal a slimy, brown or even black layer. Many people suspect the appliance is broken or the laundry is being washed incorrectly, but experts say the cause is more mundane: microorganisms are growing there. The German portal “MyHomeBook” explains how these deposits form and how to avoid them.
How the deposits form
Residues of detergent and fabric softener remain in the compartment. Bacteria and fungi can break them down, since the surfactants and other ingredients in these products can serve as food. If residues build up over a longer period, the activity of these microorganisms produces a brown or black layer. House dust may also contribute.
The compartment is an especially favourable environment for microorganisms because moisture often remains after a wash cycle, while more residue accumulates with each subsequent wash. Bacteria and fungi therefore have both food and moisture. If the compartment dries out, it becomes much harder for them to multiply.
Temperature and detergent type are not decisive
Wash temperature does not affect the formation of the deposits, because water enters the machine cold and is heated only later. Whether powder, liquid detergent or a product containing bleach is used is also not the deciding factor. The main problem is that the compartment goes uncleaned for a long time.
Is it harmful to health?
According to the experts, if the deposits are simply rinsed away, bacteria and fungi can end up on the laundry, leave stains and cause an unpleasant smell. Whether they also pose a health risk cannot be stated definitively, as it depends on the specific circumstances.
How to get rid of them
If dark deposits are already visible, the compartment should be removed from the machine completely and washed thoroughly. To prevent buildup, it is recommended to clean it about once every two months. After each wash, leave it slightly open or pull it out entirely so that it can dry.
