What is a Water Butt?

A water butt is a simple yet effective container designed to collect and store rainwater from your roof. Typically connected to your home’s guttering system, a water butt provides a free, sustainable water source for your garden.

In the UK, where water demand is rising due to climate change and population growth, this traditional garden tool has become an important part of modern sustainable living. Garden irrigation can account for a significant portion of household water use—especially in summer, when hoses and sprinklers can use up to 1,000 litres of water per hour. That’s more than twelve bathtubs’ worth in just one hour.

Understanding what a water butt is—and how to use one—can help reduce your reliance on mains water, lower your bills, and keep your garden flourishing even during hosepipe bans. This guide breaks down everything you need to know about water butts, from how they work to how they help the environment.

What is a Water Butt?

A water butt is a container—usually made of plastic, though other materials exist—used to collect rainwater from roofs via downpipes. Most are fitted with a diverter that channels water from the gutter into the water butt, allowing it to fill during rainfall. Once full, excess water flows back down the regular drainage system, preventing overflow.

Stored rainwater is then accessed through a tap at the base, often used to fill watering cans or connect to irrigation systems. A standard UK domestic water butt holds around 200 litres—enough for about 20 watering cans.

How Water Butts Work

Water butts are connected to your guttering using a diverter kit, which redirects rainwater into the container while allowing overflow to continue through the drain once it’s full. The setup is gravity-fed and doesn’t require electricity or pumps.

Key components include:

• Inlet/diverter – fitted to the downpipe to collect roof water.
• Lid – prevents debris, algae, and insect from entering.
• Tap or spigot – located at the base for easy access to water.
• Overflow/connector – allows linking of multiple butts for extra capacity.

Rainfall in the UK adds up quickly. Even a modest shed roof (7×5 ft) can collect over 600 litres of rainwater over a typical summer. Larger house roofs can yield over 24,000 litres per year—equivalent to 150 barrelfuls.

Benefits of Using a Water Butt

1. Reduces Mains Water Use

Every litre of rainwater you collect saves a litre of treated mains water. With the average Brit using around 150 litres of water per day, using rainwater for gardening can make a noticeable difference—especially during dry spells when demand spikes.

2. Lowers Your Water Bills

If you’re on a water meter, every drop counts. Swapping mains water for free rainwater can cut summer bills significantly, particularly if you water regularly.

3. Eco-Friendly and Sustainable

Rainwater harvesting reduces the burden on public water supplies and storm drains. By holding back runoff, water butts help mitigate local flooding and reduce water treatment energy and emissions—cutting your household’s carbon footprint.

4. Healthier for Plants

Rainwater is naturally soft and free from chlorine, making it better for most plants—especially those that prefer acidic or neutral soil. It’s also typically closer to ambient temperature, preventing shock to roots compared to cold tap water.

5. Drought Resilience

During hosepipe bans, stored rainwater in your butt remains accessible. Many bans permit watering with a can if it’s not drawn from the mains. With a full butt on hand, you can keep your garden going even when restrictions are in place.

Choosing the Right Water Butt for Your Garden

Water butts come in a wide range of sizes, shapes, and styles. Here’s what to consider:

• Capacity – Small (100–150L) suits patio gardens; Medium (200–250L) is ideal for most gardens; Large (300L+) or multiple butts are best for heavy users.
• Shape – Slimline butts fit tight spaces, while larger round barrels offer more volume. Decorative options exist if aesthetics matter.
• Materials – Look for UV-stabilised, food-safe plastics or recycled materials. Avoid using repurposed containers unless you’re sure they’re safe for gardening.
• Compatibility – Ensure the diverter fits your downpipe size (typically 65mm square or 68mm round in the UK).
• Accessibility – A raised stand improves ease of use and flow rate. Check the tap is easy to reach and that the lid allows for cleaning and access.

A water butt is a smart, low-cost way to make your garden more sustainable, resilient, and cost-efficient. By collecting free rainwater, you reduce your dependency on mains supply, protect the environment, and give your plants a healthier drink.

Whether you’re working with a small patio or a large allotment, there’s a water butt to suit your space. Installation is straightforward, maintenance is minimal, and the long-term benefits—both environmental and economic—are considerable.

If you’re looking for a simple first step towards a greener garden, fitting a water butt is a great place to start. You’ll be ready for dry spells, save money, and help safeguard the UK’s water future—one rainfall at a time. Check out our full range here.