Three tanks of 400 litres making a total system capacity of 1200 litre these tanks are narrow at only  360mm wide well suited to the boundary on many detached residential properties where space can be available at about a metre wide . Tank dimensions are on the rainharvestingpage of waterwhileaway.co.uk . Picture to the right shows the 400 litre unit and pictures below show the three main sizes of tanks we supply . Choice of pump either a submersible or a surface pump connected to the brass insert in tanks .