Why do I get mould in my Washing Machine?

It is becoming far more common to find complaints about people finding their
washing coming out of the machine covered in some kind of mould, or a slimy
substance. This is a build up of bacteria that has become trapped in the machine
and also comes with a very unpleasant odour if not investigated and resolved.

Strangely enough some machines are far more prone to this problem than others,
generally this is due to some machine having a plastic outer tank.

What tank should I look for when selecting a washing machine?

It would be very rare for a similar problem to be found in a washing machine that has
a stainless steel outer tank. Obviously this cannot be categorically confirmed, as
there are always exceptions, and it can depend on the amount and make of washing
detergent that is used.

Unfortunately, due to consumer pressure, manufacturers’ aim is to save costs when
designing washing machines, and stainless steel tanks are no longer the first choice.
In fact most modern machines do have the plastic tanks.

As we all know, stainless steel is an excellent material, which is why it is widely used
in products designed for the kitchen and, indeed, for medical purposes, but it does
come with a much higher price tag.

The surface of the plastic used for outer tanks is not only not as smooth as stainless
steel, but also can have holes through the surface, giving two issues when in use in
your washing machine, over the stainless steel tank.


For environmental reasons many people are switching to lower temperature
washing, and many detergent manufacturers have products on the market that claim
to work efficiently at these lower temperatures.

Liquid detergents have also become much more popular and, in fact, many people
will only use the liquid detergents. One thing to bear in mind with these products
is that they do not have preservative systems, which means there is no bacterial
protection for your washing machine or your laundry.

Bleach was originally included
in these detergents but claims for damaged clothing has meant bleach has generally
been removed. The problem was this detergent needed to be shaken every time
before use, as the bleach would always drop to the bottom of the container. The
bleach has been replaced with brighteners, but this does not offer any protection
against bacteria.

Using these new liquid detergents, along with lower temperature wash cycles,
means that bacteria is not destroyed and can continue to thrive in your machine.

These factors, coinciding with a plastic outer tank, can result in a machine which is
infected with bacteria. Obviously if you run the occasional high temperature wash
cycle in an empty machine, and remember not to keep the door closed between
washes, this will help to reduce the possibility of mould growth.

If your machine does have bacteria present, it will become noticeable as black spots
or a slimy residue on your washing. Your main aim when doing your weekly laundry
is to produce clean clothes, especially where children are concerned, not to wash
your clothes in a bacteria laden machine.

Once you start to notice the black spots on your clothing, you will probably also start
to notice a really unpleasant smell.

You will need to call in a Service Engineer as soon as you start to notice this
problem, and feel sorry for him because when he has to put his head into the works
of the machine, the smell can be overwhelming.

Are machines available with stainless steel tanks?

The answer to this question is yes, but only on a much more expensive washing
machine. In fact, you can buy a lower priced machine for the same price as the
stainless steel outer tank – a sobering thought.

If you are aware that there is a possibility of this bacteria infecting your machine, you
can certainly do something about it before it becomes a major problem. You can run
a regular empty machine high temperature wash, and by leaving the door open on
your machine it allows it to dry out and bacteria does not breed so easily on a dry

Your other option would be to select the more expensive machine with the stainless
steel outer tank.

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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