Mould/mildew on washing machine door seal, what causes this and how to avoid

Mould/mildew on washing machine door seal, causes and how to avoid

One of the primary reasons for outbreaks of mildew and mould on washing machine door seal is the growing popularity of low heat washing programs. Most people tend to select wash programs at around 40 degrees centigrade (104 F). In many, cases this may drop as far as 30 degrees (86 F). While it may be true that the low heat wash is a considerable energy saver, it may not be such as great idea in terms of hygiene. These low temperatures coupled with trapped moisture makes the area behind the machine door seal an ideal propagation ground for bacteria and mould. If mould is allowed to develop here unchecked, it will release a musty odor that can be quite unpleasant. If you reach under the washing machine door seal and run your hand across the rubber, it is possible to feel the black sludge that has developed there. This is indicative of mould or mildew.



An issue of concern here is the material used in the construction of the door seal. This is primarily a highly porous, breathable type of rubber. If it is not properly maintained, bacterial and fungal spores can infiltrate into the pores of the rubber. Over time, the spores multiply leading to a mildew infestation, which can be difficult to get rid off. In extreme cases, this mould can cause permanent damage to the structural integrity of the seal.

A further complication here is the role played by the new generation of environmentally friendly liquid detergents and the ever popular color safe detergent. The common denominator to both these products is their lack of any bleaching agent. While this might make your detergent ‘safe and gentle’ they are absolutely incapable of dealing with any form of mould or mildew. 

Mould and mildew are essentially 2 types of fungi that are known to thrive in a warm, moist environment. Apart from the musty odor they are likely to cause in a washing machine, there are several health risks associated with exposure to them. Respiratory ailments such as asthma and allergic reactions are common. In many cases, mould on washing machine door seal is transferred to clothes and causes skin rashes and irritations.

Mould/mildew build ups can also be caused when dirty, stagnant water from the sink drains enter your washing machine. This waste water can contain all sorts of organic waste, debris, and food residue. If this water infiltrates the machine, there is every possibility for some of these materials to get trapped beneath the rubber seals of the door. Such residue provides the ideal foundation for mould to grow and multiply rapidly. Simply draining away the waste water is of little use in such situations and you may be required to clean out the door seals thoroughly. This type of problem is generally indicative of a plumbing or installation flaw. The presence of a u-bend is essential to make sure that there is a strong barricade between your washing machine and any drain pipe. If your machine releases water into a drain directly, there is every possibility that waste water from the drain can seep back into your appliance. 

How to clean washing machine door seal with bleach 

Most manufacturers recommend cleaning the washer door seal with bleach and provide details in their product instruction manuals. For the purpose of clarity, however, we will examine how to clean washing machine door seal in detail.

Before you start, make sure that your appliance has been switched off and is disconnected from its electrical outlet. Make sure that there are no clothes left in the machine drum while you are cleaning it. Running your hand under the seal will allow you to physically remove any black slime that may be deposited there as well as any tiny objects that may be trapped. The machine door should be left open at this stage.

Open any windows in your laundry room to ensure there is adequate ventilation during the length of the cleaning process. This is important when you are working with chlorine bleach, as it tends produce fumes that are quite noxious in nature. Always wear good quality cleaning gloves when you are handling bleach, as this can safeguard against the possibility of burns.

Measure out a gallon (3.8 liters) of water (warm) into a bucket and add 3/4 cup (177 ml) of bleach. Stir the mixture with a clean white piece of cloth or towel. (The use of a colored cloth is not recommended as it may get damaged with exposure to the chlorine bleach.)

Make sure the cleaning cloth has been properly soaked with bleach before applying it to the door seal. The rubber seal extends all around the door cavity and you need to make sure that the chlorine bleach is applied to the entire surface area. Fungal spores may be trapped anywhere along the surface of the seal due to the porous nature of the rubber material that is present. The door seal is quite malleable and it is possible to fold it back or lift it out slightly. This allows you to access hard to reach areas and some of the deeper folds within the door seal. But, be gentle while you are handling the seal as it is quite delicate and may easily be torn if excessive pressure is applied. 

After you have made sure that the entire surface area of the seal has received a thorough application of diluted bleach, you can allow the area to rest for 5 minutes, while the door of your appliance is left open. This allows the bleach to carry out its anti bacterial duties more efficiently and will thoroughly destroy any mildew build ups, mould residues, slime, and it will also help deodorize the seal.

You may finally proceed to wiping out the seal with a clean dry cloth to remove the wet bleach. Wipe vigorously to make sure that all solid fungal residues and other existing stains are completely removed. As far as possible, do not use the washing machine immediately after cleaning the seal. Let it rest overnight or for a couple of hours with the door ajar. This will give the insides of the machine tub as well as the rubber seal ample time to dry out completely.

Most manufacturers also advocate that you run a service or maintenance wash on a monthly basis to get rid off any mould or mildew deposits. This is essentially a hot water wash that is run without any clothes in the tub. This should be run using bleach or any other powder detergent that utilizes some form of bleaching agent.

Other Causes for mould on washing machine door seal

In most households, it is common for the washing machine to be housed in a closed, humid environment that aids the growth of mould/mildew. (Typically, large homes have separate laundry rooms located in minimally ventilated basements.) 

Quite often, clothes put into the washer have organic materials or food particles attached to them. During the wash cycle it is common for some of these particles to get trapped within the rubber seal. This eventually leads to fungal infestation.

Some of the more technologically advanced high efficiency appliances available in the market today tend to get completely sealed when the door is closed. This traps moisture within the drum area and seals, which enhances mould formation.

Over time, changes have occurred in consumer laundry habits including the use of less bleach. Correspondingly, the possibility of organic residues and biofilms accumulating has increased, which heightens the occurrence of mildew, mould, and musty odors.

Some Methods to Prevent mould on washing machine door seal

If your laundry room is located in a closed, humid location, consider the use of a dehumidifier that can help deter the growth of fungus and mould.

Do not leave wet clothes lying in your machine tub overnight or for any extended duration of time. The moisture contained within them will enhance the possibility for mould or mildew to form within the machine drum and seal.

Whenever possible, leave the machine door ajar to enhance the flow of air within your appliance. This creates a drier environment that is not so conducive for the growth of mildew. 

Wipe down the insides of your machine tub with a dry cloth after a wash to ensure it remains moisture free. Pay extra attention to rubber machine door seal, making sure that it remains as dry as possible.

Only use the recommended amount of detergent. Excess detergent will create a soap scum that is responsible for forming residues that get caught within the folds of your machine seal. This semi solid residue is often responsible for increasing the occurrences of mould and bacteria. Only use a recommended detergent with a HE washing machine. Using a regular detergent with such a machine will generate excess suds. These suds can form a biofilm on the insides of your door seal that can encourage the growth of mould.








Disclaimer: The information provided has been prepared as a guide only and the steps taken are likely to vary for different appliance models. We strongly recommend using a qualified engineer to undertake major repairs and fault finding.


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