Can bath water be reused?

By Benjamin Clarke | Published on 12th April 2022

In 2006, a survey of over 6,500 Japanese participants revealed that 55% of them reused their bath water for other purposes. In the UK , a similar survey would probably result in a much lower percentage of people responding that they made use of their bathwater again after having a bath.

However, reusing bath water is actually a more sensible idea than it sounds and doesn't necessarily mean members of your family queuing up one after another to get in a progressively colder and dirtier bath. Many of us, without realising it, actually use potable water (i.e. water that is safe to drink) to wash our cars or water our plants. Even at the best of times, this is a waste of drinking water but during heatwaves and periods without much rainfall, misusing water in this way is a very serious issue and can exacerbate water shortages.

Reuse bath water on plants

The Royal Horticultural Society has said that our gardens are not particularly fussy when it comes to the type of water needed for the plants to grow. Water that has already been used once in our homes is called 'grey water' and the RHS has said that there is no problem with using grey water on our garden plants - they are definitely hardy enough to handle it and it is actually recommended for short term use during hot summer months.

It's important to note that grey water should not be used on crops or edible plants as untreated water can contain pathogens that are not suitable for human consumption.

Reuse bath water on cars

Giving your car a good wash can use a lot of water and filling up your bucket or pressure washer from the kitchen tap is really a huge waste of perfectly good drinking water. If you don't have a separate outdoor tap then you could reuse the water from a bath to wash your car, particularly if you don't tend to use essential oils when you have a soak in the tub.

From time to time, certain areas of the UK will also be subject to hosepipe bans in a bid to save water during times of drought. Hosepipes are guilty of getting through a lot of water, so reusing bath water to wash your car is a great way of doing your bit for the environment and getting around the ban.

Reuse bath water in the toilet

This is not going to be for everybody, but if you are concerned about the amount of water you use in your home, either for environmental reasons or because you're on a water meter, then using your bath water for flushing the toilet a few times is a great way of repurposing it.

While there are specific systems you can have installed that enable you to reuse grey water, one of the simplest ways is to fill a bucket and pour it directly down the toilet. This saves a flush and will get rid of whatever is in your toilet pan quickly and effectively.

Yes it might initially seem a bit odd to use your old bath water this way, but it really is a fantastic method of recycling water!

Reuse bath water for washing your dog

If you've just had a bath, then it's perfectly possible for you to use at least some of that bath water to wash a dirty dog (or other pets in need of a wash)

The water that you use to sud up the shampoo and rub into your dog's fur could easily come from previously used bath water, though we appreciate that to rinse you may want to use new water from a shower head. Nevertheless, your dog won't mind where the water comes from and you'll have the satisfaction that some of the water has been repurposed.

Needless to say, bath water should not be reused as drinking water for your dog.

When not to reuse bath water

While recycling old bath water is a fantastic option in many instances and will help in reducing your water usage, there are some instances where it's simply not healthy to do so.

As mentioned above, grey water should not be used on any plant that will be eaten as it contains germs and pathogens that are capable of making humans ill if consumed.

Likewise, grey water should never be used for drinking water either for humans or pets. As well as making you ill, it will also taste horrible, so it's absolutely off limits.

Because washing dishes in a sink uses a lot of water (more so than a dishwasher) many people wonder if bath water can be repurposed for washing up after cooking. However, due to germs and pathogens contained in grey water, it is unsuitable for washing up plates, pans and utensils and should not be used. Stick to water from your kitchen tap for washing dishes!

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