Water butt and tap fitting guide

Almost 100,000 litres of rainwater falls on our roofs each year, so harvesting rain or ‘greywater’ in a water butt is the perfect way to use natural resources to keep your garden healthy, even during a hosepipe ban or drought. A water butt can be connected to a downpipe so that it collects rainwater from your gutters. But how do you get quick and easy access to the collected water, without making several trips across the garden?

Types of water butt

Water butts come in various sizes and styles, so think about how much water you may use, the space available, and your budget. The bigger the water butt, the longer the water will last during dry summer months, however if space is tight, ‘space saver’ butts have a smaller footprint so are good for small gardens.

If you’re collecting water from a downpipe, a rain diverter will redirect water into the butt. Once it's full, excess water flows back down the drainpipe. To fit a diverter, your butt will need a hole in the side - many come with the hole already fitted. An alternative way to collect rain water is to fit the drainpipe through a hole in the lid of the water butt, however you will need an overflow or think about where any excess water will flow when the butt is full.

Locating the water butt on a stand makes it easier to fit a watering can under the tap. Make sure the stand is stable, on a flat surface and will take the weight of the water butt when full of water.

Most water butts also come with a lid to keep out unwanted debris and insects. If you have children, you may want to look for a lid with a childproof fitting. Fitting a gutter filter will also stop leaves and debris from flowing into the water butt.

Types of water butt tap

In order to fully utilise a water butt, you will need an access point or water butt tap, from which you easily draw water for a watering can, attach hosepipes or even link several water butts together to create a complete water collection system.

This guide to gives you the rundown of how to replace your old tap with a new one, as well as some alternative ways to access your rainwater from a water butt.

Water butt taps are fairly standard, but there are a few options you may want to consider. A fast flow tap is usually the best option if you just want a functional design that allows you to water your garden efficiently, although for a cheaper price you can go with just a basic replacement tap.

You’ll find more decorative options made from materials like brass, which might be a better choice if you have a wooden water barrel or something more décor-led than a regular plastic water butt. There are also more elaborate designs with things like animal motifs if you want to create an outdoor feature.

Installation tips

How to drill a hole in your water butt

If your new water butt doesn’t come with a ready-made hole or an old tap, you will need to drill a hole to fit the tap. DIY water butts made out of old water barrels or plastic canisters will likewise require some modification. Even without a hole in place, a shop-bought model will often come with a flat area near the base suitable for drilling.

Standard-size water butt taps come with a pipe attachment of around 25 millimetres (0.5 inches) in diameter, but the best thing to do is to buy the tap first and check on the packaging - or measure the width yourself and draw directly on to the water butt.

You will need an electric drill and the correct-sized drill bit – a flat bit can work on thicker material but you may find a holesaw is more effective on thin plastic. Start with a hole that’s slightly smaller than the diameter of the tap if possible – you can always make it bigger.

You might also want to place some supporting wood across the outside and inside of the water butt where you will be drilling and use a slow speed on your drill, to avoid the water butt splitting. Alternatively, if the material is quite robust, like wood, you can use masking tape. Finish off by sanding the hole to get rid of any splinters or shavings.

Fitting the water butt tap

Once the hole is created, most water butt taps are easy to install. The kit should come with washers to screw in place on the inside and outside of the water barrel or butt. Check that the tap is securely fitted by switching it to the ‘off’ position, and filling the barrel with enough water to cover the thread (pipe connector). If the tap drips, you may need to tighten the fitting.

How to link water butts

If you have something more ambitious in mind for your garden rainwater, or already have more than one old water butt, you might want to create a linked water system, in order to increase your water storage and provide more resources for your hosepipe.

For example, linking three water barrels is fairly simple. One method is to link the containers at the bottom, and you can often use an existing old tap or holes without having to make a lot more. Bottom-connected butts are also comparatively faster filling and will also collect greywater at roughly the same rate. The disadvantage to this method is that old leaves can collect in the water at bottom of the butts, and cause blockages in the connectors and water butt taps.

To set up bottom-linked water butts, you just need to drill a second hole in what will be the middle water butt in the system (usually opposite the first hole), and then in the third water butt as well. Again, the standard size for linking connectors is 25 millimetres but check before you start.

Top-linked water butts also work well and if they are bought from a store, you may not have to drill extra holes to connect them. However, you may need to buy a specific linking kit to go with a specific range of water butts. They will also only fill up with water one by one, meaning you may have to switch your hosepipe attachment if there has not been enough rain to fill the third barrel.

With top-linked butts, make sure the water outlet connecting the first top-linked butt to the second is lower than the downpipe or diverter which is bringing the rain water in. The hole in the top of the second water butt should also be lower than the outlet of the first, and so on across the chain.

Alternatives to water butt taps

Installing a water butt tap is not the only solution to filling your hosepipe from a greywater collection: you can also buy pumps which are placed inside the container and exert enough water pressure to feed the hosepipe. These are mains-powered by way of an extra-long flex, so the obvious drawback is that the eco-friendly method of conserving rainwater may be slightly offset by the energy the pump uses. However, most models are quick, taking around 5-6 minutes to empty a standard-sized tank of 200 litres.