Builder’s Warehouse supply Efficiently harvest rainwater, Capture and store up to 5,000 liters of rainwater with the durable poly slimline tank (BWSL5000). Its narrow profile is perfect for maximizing usable area around your home or garden. Constructed from durable poly, its slender design fits neatly against walls and fences. Its space-saving design (BWSL5000) makes it ideal for properties with limited space.