Rainwater Butts And Downpipes

What this is

A roof sheds a surprising volume of water into a small number of downpipes. A water butt intercepts part of that flow and holds it for garden use, and the diverter that connects it sends the rest on down the pipe as normal once the butt is full. The second half of that sentence is the part that matters most.

Telling whether your home needs it

A garden watered from the mains through summer, a downpipe discharging onto a path where water then stands, or a gully that overflows in heavy rain are all reasons to look at this. Green algae staining down a wall beside a downpipe usually marks a joint that has been leaking for some time.

What the job involves

The butt needs a firm, level base raised enough to get a watering can under the tap, because a full butt is heavy and an unstable one is a hazard. The diverter is cut into the downpipe at the height of the butt inlet, using the template supplied with it. Fitting a lid and a fine mesh at the inlet keeps out leaves, insects and light, which keeps the stored water usable.

Things to watch

Make sure the overflow route is genuinely clear and discharges away from the foundations, not against the wall. Stored rainwater is for the garden, not for drinking or for filling anything that connects to household plumbing. In cold weather empty the butt or leave the tap open, since a solid block of ice will split the container.