Make Your Own Water Butt

Why Collect Rainwater in the First Place

The unpredictable nature of British weather means one summer your garden might be waterlogged, while the next you could be watching plants wilt during a prolonged dry spell. This makes storing rainwater a sensible approach for anyone who tends a garden or allotment.

If you live in parts of England that regularly face water restrictions, particularly the South East and East Anglia, you will already know the frustration of hosepipe bans. Having your own rainwater supply means you can keep watering when mains restrictions come into force.

Rainwater is generally free to collect, which matters if you are on a water meter. Every litre you collect is a litre you do not pay for. Over a growing season, this can lead to savings, especially if you have a large vegetable patch or greenhouse that needs regular attention.

There is also a horticultural benefit. Rainwater is naturally soft and slightly acidic. Plants that prefer ericaceous conditions, such as rhododendrons, camellias, azaleas and blueberries, often do better when watered with rainwater rather than hard tap water. In areas with chalky or limestone mains supplies, this difference can be noticeable.

Beyond your garden, collecting rainwater helps reduce stormwater runoff and eases pressure on natural water resources. It is a simple way to make your gardening more sustainable.

Choosing a Container

A water butt does not need to be anything fancy. The basic requirement is a watertight container that can hold a reasonable volume and withstand being outdoors year round. Many people use food grade plastic barrels or drums that have been cleaned out. These are often available from industrial suppliers, catering companies or online marketplaces.

Containers that previously held food products, such as olives, fruit juice concentrate or cooking oil, are generally safe choices. Avoid anything that has stored chemicals, fuels or unknown substances. Even after thorough cleaning, residues can remain and potentially harm plants or contaminate your garden.

Size depends on your available space and how much water you expect to use. A standard capacity is around 200 litres, though smaller and larger options exist. If you have room, consider installing more than one butt. Linking them together with overflow pipes means surplus water from one fills the next, maximising your storage during wet spells.

Colour is worth thinking about. Dark coloured containers, typically green or black, help discourage algae growth by blocking light. They also tend to blend into garden surroundings more easily than pale or brightly coloured alternatives.

Your situation may be slightly different. ask a question below ↓ and our editorial team will reply with our advice.

Setting Up Your Water Butt

Position your water butt beneath a downpipe from a roof gutter. This is where the water will come from. A shed, greenhouse or house roof all work well. The larger the roof area draining into your chosen downpipe, the faster your butt will fill during rain.

You will need to raise the butt off the ground so a watering can or bucket fits beneath the tap. Purpose made stands are available, or you can build a simple platform from bricks, concrete blocks or sturdy timber. Make sure the base is level and solid. A full 200 litre butt weighs over 200 kilograms when you account for the container itself, so it needs stable support.

To get water from the downpipe into the butt, you have a few options. Diverter kits are widely sold and allow you to cut into an existing downpipe, channelling water into the butt while directing overflow back into the drain. Alternatively, you can cut the downpipe and position the butt so water falls directly in from above. This arrangement needs a secure lid or mesh cover to keep out debris and prevent mosquitoes breeding, which is essential during warmer months.

Fit a tap near the base of the container if one is not already present. Plastic barrel taps designed for this purpose are inexpensive and straightforward to install. You will need to drill a hole of the correct diameter, insert the tap fitting with a rubber washer on the inside, and tighten the nut to create a watertight seal.

If you are renting or working on a community allotment, check with your landlord or plot manager before installing a water butt, as some sites have specific rules.

Maintenance and Practical Tips

A water butt requires minimal upkeep, but a little attention helps keep things running smoothly. Check the inlet regularly and clear any leaves or debris that might block water flow. A simple mesh filter over the opening reduces the amount of material that gets in.

In autumn, when leaves are falling heavily, you may need to clear blockages more frequently. Some people fit a leaf guard to the gutter itself, which helps keep the whole system cleaner.

Before winter, consider whether your butt might freeze. In most parts of the UK, a full container will not freeze solid, but a tap left full of water can crack. Drain the tap fully before closing it during cold spells to reduce this risk. If your area experiences hard frosts regularly, lagging the tap with insulation material offers extra protection.

Over time, sediment may collect at the bottom of the butt. Every year or two, it is worth emptying the container and rinsing it out. This prevents a build up of sludge and keeps the water cleaner.

Remember that stored rainwater is not suitable for drinking, cooking or personal hygiene due to potential contamination from roofing materials and debris. Keep it for garden use only.

For more information on water saving measures and any local restrictions that may apply, check your water company's website or visit GOV.UK for guidance on water use during drought conditions.