Rainwater can be collected from the roofs of homes, garages, greenhouses and other garden structures as long as they have gutters and a drain pipe.
Water butts are designed to collect water from either open or closed drain pipes. Closed drain pipes can be easily tapped into with a rain water diverter kit.
Clean water butts annually to prevent disease spread. use collected water on established plants rather than seedlings. If multiple butts are used, rotate use to keep stores fresh.
Local councils and DIY stores are good places to purchase basic plastic water butts. It is easier to access the water if the butt has a tap at the base and sits on a stand, either ready-made or improvised with a pile of bricks. More expensive butts moulded to look like beehives or terracotta urns are an attractive option, as are recycled wooden barrels.
As climatic change models suggest an increasing proportion of rain will fall in winter, it may become cost effective to build-in rainwater storage when constructing new homes. This usually involves sinking a large tank somewhere in the garden, pumping water out for use in the garden or for domestic tasks such as flushing toilets. However, the more pumps and piping that is required, the greater the cost and carbon footprint of such schemes.
The UK Rainwater Management Association can advise on purchase and installation of rainwater harvesting systems.