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How much water can you save by using a water butt

Posted by Callum VP, on October 19, 2020.

More and more people are choosing to store rainwater and use it in their gardens and around the home. One of the easiest ways to do so is to use a water butt. But how much water can you save by using a water butt? We explore the possibilities in more detail below.

What is a water butt?

Quite simply, a water butt is an overground water tank attached to the roofline downpipe that is used to store rainwater. It is a wonderfully cost-effective way to lower water bills and to help grow a flourishing garden, as rainwater contains the most natural elements needed by plants.

How much water can you save using a water butt?

According to the Consumer Council for Water, the average UK household collects enough rainwater to fill 450 water butts (although this depends on the size). Smaller water butts usually hold around 100 litres and are cheap to buy, while at the more expensive end of the scale you can buy a tank that holds as much as 1,000 litres (providing you have the budget and room to accommodate).

When it comes to watering your garden, a sprinkler or hosepipe places a lot of strain on water resources, and subsequently your bill (if using a water meter). Both of these options can typically use up to 1,000 litres in a single hour, and is also not helpful for the local environment. 

Save Water Save Money – who distribute water saving solutions around the world – say that if every home in England collected a single water butt’s worth of rainwater a year (or 160 litres), this would save 4 billion litres of fresh water being  used during the same period.

The Water Services Regulation Authority say it costs about £1.50 an hour to water a garden with a hose or sprinkler, which adds up to a fair amount of money across the course of the year. Of course, costs will vary depending on the jet speed, and the provider price plan you are on, which means it could cost less, or even more.

If you choose to use a watering can filled with tap water, the equivalent cost will be around 50p per hour. Meanwhile, using harvested water will not cost any money at all.

Greywater and watering times 

Another option is to use recycled washing up and bath water in the garden, although the pH levels in greywater are around a third higher and are not as beneficial to your plants as natural rainwater. 

A side effect of using water with high levels of acidity (which applies to both tap and greywater) is that over a long period of time plants can begin to develop yellow leaves, which could be a sign of chlorosis. 

When you water your garden will also play a central role in the savings you can make. For example, watering during early morning or in the evening will lower the amount of water evaporation. It is also a good idea to use mulch coverings on borders and beds (bark, wood chips, gravel etc.) as this helps reduce evaporation and keeps the moisture active for longer. 

How to clean and maintain a water butt

Cleaning the outside of a water butt is relatively straightforward as long as it is done on a fairly regular basis to avoid a build-up of dirt and grime that can be more difficult to remove.  

If you have water inside, use this to wipe down the outside of the butt with soap to remove any dirt before rinsing and letting it dry naturally. This same process should be carried out for the lid, while also checking it is maintaining a tight fit. 

It is also a good idea to clean the inside of the water butt as over time grime, algae and sludge will develop due to the route taken by the rainwater from the roof, into the guttering and into the downpipe, where these types of materials are present. 

During the winter you should ensure the tank is empty (this will also make it easier to clean) to avoid the butt freezing over and potentially affecting the downpipe and causing flooding. 

There are specific non-toxic products you can buy that are designed for cleaning the inside of a water butt and will also help improve the quality of the water during periods of storage. They usually come in tablet or liquid form and work to prevent odours developing, while stimulating rainwater micro-organisms.

You can also add water purification tablets to prevent algae from growing during periods where there is not much rain and water in the butt is not being used. 

One final tip is to invest in copper or silver discs which can be used inside the butt to mimic the germicidal properties of real industrial silver. This is a method used in both drinking water purifiers and hot tub filters, as they reduce bacteria levels while also killing off parasites and fungal micro-organisms.