A water butt from a plastic drum: how it works

Wide-neck drum used as a water butt beneath the downpipe of a garden shed

The short answer

A 220 litre lidded drum under the downpipe is the cheapest fully-fledged water butt: UV-resistant HDPE, a wide opening for the watering can and for cleaning, and a lid to keep out leaves and mosquitoes. If you want to avoid algae, go for the black 220 litre wide-neck drum – dark plastic lets no light through.

Which drum is suitable?

Drum	Suitable for
120 litre lidded drum	small roof areas, watering balconies and greenhouses
220 litre lidded drum with clamp ring	the standard for garden shed or garage roofs
220 litre wide-neck drum, black	best choice against algae growth, very robust
200 litre lidded drum, used	budget solution with the same function

Fitting a tap – in 10 minutes

Drill a hole about 5 cm above the bottom of the drum (drill bit size to match the tap thread, approx. 19–20 mm for 3/4 inch).
Insert the AFT tap with external thread and plastic nut from the outside and tighten the nut from the inside – the nut seals against the drum wall.
Stand the drum on a sturdy base (concrete slabs, a plinth) so that the watering can fits under the tap.

Algae, mosquitoes and frost

Algae need light: dark drums stay clean for longer; place light-coloured drums in the shade.
Mosquitoes are kept out by the lid – one of the biggest advantages over open water butts.
Frost: Empty the drum before winter and remove the lid or turn the drum upside down – otherwise freezing water will burst the wall.

You will find all sizes from the 5 litre mini drum to the 220 litre drum in the Drums category.

As of: September 2026