Garden Plumbing

Installing a Water Butt

It seems that no matter how much rain the UK sees throughout the year, a few weeks of good weather will see the threat of hosepipe bans hitting the news all too frequently. Being able to tap into your own supply of rain water for things like watering plants or washing the car has considerable appeal, particularly in those areas where hosepipe bans are a yearly feature. Although installing a water butt and rain diverter may seem like a simple job, there is definitely a right way and a wrong way to do it.

Buying a Rain Diverter

Water butts are available in a variety of sizes, styles and colours, for an equally wide variety of prices. You can buy water butts online or from the big DIY sheds (B&Q, etc.,) or you may be able to source them at a reduced rate directly from your local council. Some water butts will come with a rain diverter kit, whilst others will require you to buy a diverter kit separately.

Make sure that you buy a diverter which is the correct size for the diameter of the downpipe. A rain diverter will normally consist of the main body containing a leaf trap, a linking pipe (either rigid or flexible) and a threaded coupling which is used to attach the pipe to the water butt. Simply drilling a hole in the downpipe and poking a length of hose through it is definitely not the way to harvest rainwater efficiently, so don’t forget this important part of the setup.

Step 1 – Positioning the Water Butt

Installing a water buttSome water butts have a separate base which can be placed in the desired position and then levelled up before the water butt itself is placed on top. Some will sit directly on the ground. If the area around the bottom of the downpipe is grass or soil, it is a good idea to lay a paving slab on a bed of sand for the water butt to sit on. This will help to keep it stable and upright if the ground below is saturated.

Position the butt close to the wall and around 300mm from the downpipe. This allows you room to work, whilst keeping the length of diverter pipe you need to use to a minimum. Lay a spirit level across the top of the butt to make sure it is sitting level.

Step 2 – Mark and Cut the Downpipe

Use a spirit level or a straight-edge to mark the level of the top of the butt onto the downpipe. Using the template supplied with the rain diverter, mark how much downpipe you need to cut out below this first mark. Use a fine-toothed saw to cut out a section of downpipe between your two marks. This is where the rain diverter will be placed.

Step 3 – Fit the Rain Diverter

Fit the body of the rain diverter into the gap, using any size adaptors or rubber seals as required. The rain diverter outlet pipe should be at the bottom. Once it is firmly in place, rotate it until the outlet is facing the water butt.

Use a hole-cutter drill bit of the appropriate diameter to make a hole in the wall of the water butt. Make sure this hole is level (or even very slightly below) the level of the outlet on the rain diverter. Slot the threaded coupling into the hole, making sure that you use any supplied washers for a water-tight fit. Thread the supplied nut onto the coupling on the inside of the butt and tighten by hand.

Step 4 – Fit the Linking Pipe

Slot the supplied diverter linking pipe into the coupling, and mark where it needs to be cut off to fit into the outlet on the body of the diverter. Make sure that you leave enough pipe to fit firmly into the outlet. With the linking pipe in place, your water butt is installed. You will need to wait for the next rain to check that everything is working as it should.

You should remember to periodically disassemble the diverter to clear out any debris which has accumulated. This is particularly important if you have overhanging trees around your house. To reduce the need to do this, you can fit a leaf guard to the top of the downpipe.