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Garth’s guide to picking the best water butt for your garden

Posted by Garth the Wizard, on May 16, 2022.

Water butts are incredibly useful in the garden, they will help save money on your water bill and save your plants from a hosepipe ban too. Our garden plants love rainwater more than anything else because it’s slightly acidic – naturally! Water butts can be any size or shape, so they can be disguised in your garden or made into its own centrepiece. Garth has a simple guide so you can choose the best water butt for your garden and start collecting rainwater quickly.

Why Buy A Water Butt?


Water butts are cost-effective as rainwater is free, and we get lots of it in the UK! By investing in a water butt, the initial saving may not seem significant but over time, substantial savings can be made. Typically, outdoor water can account for 7% of your total household water, but in the height of summer, this can be significantly more.


Plants love rainwater! Those tucked away in the safety of the greenhouse don’t get watered with it as much as outdoor plants. Rainwater is slightly acidic and plants much prefer a pH level between 5-6. One of the best gardening tips to grow strong and healthy plants is to start watering them with rainwater.


Tap water is not always readily or easily available in some gardens/allotments. A water butt occupies very little room and it can be sited near to where water is required.


Water from our taps is commonly treated with chemicals such as chlorine and aluminium sulphate. Other chemicals are also frequently added such as fluoride. When water travels through older pipes it also picks up unknown levels of other substances which can be toxic to plants.

Choosing A Water Butt

Watering your raised beds and kitchen garden might be a chore, but having a water butt close to your plot will help you grow strong and healthy plants. The three important factors to consider when choosing one are size, material and budget. The size of your garden will greatly influence the size and water capacity you’ll need.

Plastic water butts are strong, light, cheapest of all and last for a very long time. Green or black are the normal colours.  Your water butt will be a permanent feature in your garden so it might be worth spending a little more on one so it lasts a long time and looks good.

Garantia has lots of water butts to choose from here. If you’d like to disguise your water butt in your garden, you could choose something that looks like a plant pot such as Antique Amphora (250 Litres) Terracotta Water Butt. This water butt brings a Mediterranean feel to your garden, whilst allowing you to harvest rainwater for your garden. Due to the unique manufacturing process, each of these tanks is a unique lifelike replica of a genuine terracotta vase. This water butt features a fixed planter cup on the top, which when lined with the geotextile fleece allows the planted area to also catch rainwater which is collected in the tank below. The high-quality threaded tap hole in the front of the tank makes the tap installation easy for you, with the water below the tap level serving as a stable base. These water butts can easily be installed on any downpipe, brightening up your garden.

Alternatively, you might like the water butt to match your greenhouse. The Garantia Green Slim Wall Tank (300 Litres) is available in a natural-looking dark green colour so it blends in well with your plot. It allows for high-capacity water storage despite only needing a small space in your garden. This tank comes with a brass plastic tap.

What Size Do You Need

To work out what size you need, it’s a good idea to take a look at your garden and the type of planters you have. Pots for example will need watering more than raised beds as they won’t have extensive root systems. Below is a rough guide and estimate.

Grow Bag

Approximately 3 litres / 5.5 pints per day in warm weather. Assume in the region of 200 litres during the growing period.

Regular hanging basket

Approximately 1.5 litres per day in warm weather depending on the construction of the basket and the number of plants in it. Assume in the region of 100 litres during the growing period.

Raised bed sized 2m by 2m with shallow-rooted plants

Approximately 3 litres per day. This can vary considerably depending on the type of ground, weather conditions and the plants being grown. Assume in the region of 200 litres during the growing period. Note that many shrubs and almost all trees need almost no manual watering.

Looking After Your Water Butt

It’s important to keep a lid on your water butt to prevent any debris or animals from getting into the water. If you do notice anything in the tank, there is no need to discard all of the water. Simply add a few drops of specially created treatment to the water to ensure that it’s suitable to use again.

It’s a good idea to clean your water butt by washing out the debris that may collect in the bottom at least once a year. A handy tip is to use a thin mesh over the end of the downpipe to make sure nothing gets into the tank in the first place.