Every few summers the same letter drops through the door: a Temporary Use Ban, or what most of us still call a hosepipe ban. The reservoirs are low, the lawn is going the colour of straw, and suddenly the only legal way to water the runner beans is a watering can and a sore shoulder. A water butt changes that. It is the cheapest, most boring piece of kit in the garden, and in a dry year it is the one I am most glad I fitted.
The job itself is a single morning. The hardest part is deciding where to put it.
Why bother, when the rain is free anyway
That is rather the point — the rain is free, and a water butt is just a bucket that catches it before it disappears down the drain. A typical house roof sheds a startling amount of water; even a modest shower fills a 200-litre butt faster than you would think. Rainwater is also slightly soft and free of chlorine, which the tomatoes, ferns and acid-loving shrubs quietly prefer over what comes out of the tap.
And when the ban arrives, a full butt is the difference between a garden that limps through August and one that gives up by the second week.
Sizing and where to stand it
How big
For a small patio or a few beds, a 100–200 litre butt is plenty. If you have a greenhouse, raised beds or a thirsty lawn, go for 250 litres or link two butts together with a connector kit. Bigger is almost always the right answer — you only regret the small one in July.
Where
It needs to sit directly under a downpipe, on firm, level ground. Soft soil is a problem: a full 200-litre butt weighs over 200 kg, and it will lean, sink and eventually topple. Lay a couple of paving slabs or a proper butt stand first. The stand matters for a second reason — you need enough height under the tap to slide a watering can underneath, and a butt sat flat on the ground gives you almost none.
What you will need
- A water butt with lid and tap — around £25 for a basic 100-litre to £60 for a 250-litre slimline (B&Q, Wickes, most garden centres)
- A butt stand or two paving slabs — stands run about £15–£20
- A downpipe diverter (rain diverter) kit — roughly £15–£25 from Screwfix or B&Q; buy one to match your downpipe diameter, usually 68 mm round or 65 mm square
- A hacksaw or a junior saw
- A tape measure, a pencil and a spirit level
That is the lot. No special tools, no plumbing.
Fitting it: step by step
- Stand the butt on its slabs or stand, hard against the wall under the downpipe, and check it is dead level.
- Mark the downpipe at the height of the diverter — usually a little above the top of the butt. The diverter instructions give an exact measurement; follow theirs, not your eye.
- Cut cleanly through the downpipe at your mark with the hacksaw. Take your time and keep the cut square.
- Slot the diverter into the gap, clipping the two pipe ends back into it. Most modern kits are a push-fit — no glue, no screws.
- Drill or cut the small outlet hole the kit specifies, then run the short connector hose from the diverter into the butt lid.
- Fit the tap to the butt if it is not pre-fitted, sit a watering can under it, and wait for the next downpour.
The diverter is the clever bit: once the butt is full, it simply sends the overflow back down the drain instead of flooding your patio. No need to disconnect anything.
Keeping the water clean
Stored rainwater goes off if you ignore it. A few habits keep it sweet:
- Keep the lid on. It blocks light (which feeds algae), keeps leaves out, and — not a small thing with children about — stops anyone falling in.
- Fit the diverter's leaf filter or pop a square of fine mesh over the inlet so grit and moss off the roof do not settle in the bottom.
- Give it a rinse out once a year, ideally in late winter before the growing season, to clear the silt.
The water will never be drinking quality, and it is not meant for filling a paddling pool. For the garden, though, it is ideal.
The mistakes that catch people out
Three, mostly. Standing the butt on bare earth, so it tilts within a fortnight. Buying one too small, then watching it run dry in the first hot spell. And forgetting the height under the tap — a butt you cannot get a can under is a butt you will not use. Sort those before you cut the pipe and the rest looks after itself.
Fit it this weekend, while the forecast still promises the odd shower. By the time the ban letter arrives, you will have a full butt and a smug expression. Both are worth having.