Why Laundry Water Turns Grey (And How To Use It)

Curious about the misty water that comes out of your washing machine? We explain what happens and what you can use it for.

Whether washed by hand or a washing machine, laundry produces wastewater known as “greywater.” The name reflects the colour of the water which is caused by dirt and laundry products like detergent and fabric softener.

You might be wondering about the finer details of greywater. Well, you are in the right place! We explain why the water changes colour and how you can re-use greywater.

The Top Reason Why Laundry Water Turns Grey

The topic is actually an interesting one although most people do not give greywater a second glance. The reason behind the colour change is simple. It happens when the water takes on different kinds of particles. These include bits of dirt, laundry detergent, fabric softener, and even minerals in the water supply. All of these things contribute to laundry water taking on a grey or milky appearance. 

Once again, most people are content to let greywater swirl down the drain. In some cases, it is even necessary to discard the water. But there are times when you can actually re-use greywater to save money and water.

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Is Greywater Toxic?

Why Laundry Water Turns Grey (And How To Use It)

Greywater can indeed be toxic. It depends on what kind of laundry detergent and fabric softener you use. When these products contain chemicals, then greywater is not considered as safe and should not be re-used. However, if you use bio-degradable and environmentally-friendly products then greywater is not considered toxic.

What Can Greywater Be Used For?

Greywater is mainly used as a means to water gardens. That is why it is so important to only use greywater that is environmentally-friendly and chemical-free. The water coming out of your washing machine is wastewater but it can replace the extra water you normally use to water your garden. This helps to saves water, which is a valuable and costly resource, and keeps your plants in top shape. 

How Do I Collect Greywater?

The most common way to collect greywater is to install a water collection system. This system connects your washing machine’s pipes to a water tank (which is usually located outside in the garden). Every time you use the washing machine, the wastewater automatically collects in the tank. You can also connect your basins and shower to this tank, increasing your home’s greywater output even more! The good news is that there are different types of tanks. So, it does not matter if you live in a small flat or a big house with several bathrooms, there is a tank system that will suit your needs.

How Difficult Is It To Install A Greywater Tank?

Things should go quickly if your home’s plumbing outlets are easily accessible. Otherwise, a good plumber is needed and he can make the necessary adjustments and connections. But the bottom line is this – installing a greywater tank is normally quick and easy, and definitely worth it. 

How Do I Water My Garden With This Tank?

There are several ways that you can use the tank’s water for your garden. One of the most popular choices is a drip irrigation system. This requires some planning and installation by a professional electrician and plumber. That aside, the drip system is fantastic for large gardens, especially big ones that need a lot of water during the hot season. 

Never use greywater to irrigate your vegetable garden. The health risks are too high. 

Is There A Time Limit To Using Greywater?

Unfortunately, the answer is yes. Greywater cannot be kept for very long periods of time. When this happens, the water tends to grow bacteria and even mould. Ideally, one should aim to use greywater within a day or 24 hours after it collects in the tank. 

Are There Drawbacks To Recycling Greywater?

Oh boy, we would like to say no but recycling greywater has some issues. You can read about the most common drawbacks below. 

Your Home Needs A Double Plumbing System

This is necessary to separate greywater from so-called blackwater. This is crucial. Whereas greywater can be re-used, blackwater needs to go down the drain and away from the home. Why? This water is contaminated with sewage and needs to be recycled at the proper facilities. 

A quick word of caution. If you use reusable nappies and wash them, then that water is considered blackwater. Never use it to water your garden.

The Risk Of Contamination

Why Laundry Water Turns Grey (And How To Use It)

Your greywater system can risk contamination if the wrong substances enter the tank. For instance, a guest uses your shower but does not know that you only use environmentally-friendly products due to having a greywater tank. They wash their hair and themselves with chemically-ladened shampoo and body wash. All of this enters the tank and contaminates the water. 

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There Are Health Risks

As we mentioned a little earlier, stagnant greywater is a perfect haven for bacteria and other bad stuff. This is not good news. Even if you only plan to dump the water in your garden, the bacteria can then contaminate the grass your kids walk on and accidentally seep into the vegetable garden you eat from. There is also the chance that uninformed persons, kids, and pets might ingest the water.

If you suspect that your child or pet drank greywater, you need to contact a doctor or vet.

Kitchen Greywater Is A High Risk

Many households with a greywater tank also connect the kitchen to this system. But the wastewater coming from the kitchen holds a particular danger – the blood, fats, and residues of organic matter can be deadly in the water. Greywater coming from bathrooms and washing machines are considered to be the safest to use in the garden. 

Rather play it safe and do not connect the kitchen to your greywater tank. Do not worry about losing too much valuable water. Almost half of all greywater in the home comes from the bathroom and the kitchen roughly contributes a meagre 8 percent. But as small as it is, it can be potentially dangerous.

A Quick Summary On Why Laundry Water Turn Grey

  • Laundry water turns grey when it gathers dirt, laundry detergent, fabric softener, and minerals during a washing cycle.
  • This type of wastewater is called “greywater.”
  • Wastewater from the washing machine is not the only type of greywater.
  • Greywater from the kitchen is generally considered usable but potentially dangerous due to the presence of organic matter.
  • Greywater can also be collected from basins, the bath, and the shower.
  • The most common recycling use for greywater is to water the garden.
  • Garden greywater is collected in a special tank that needs to be connected to the plumbing of the home.
  • Garden greywater saves utility bills, water, and keeps the garden green.
  • Greywater also has drawbacks including short shelf life, health risks, and the need to install a dual plumbing system.