New York requires rooftop tanks on buildings over six storeys, and 5,600 are wooden; three family firms still build them from staves with no nails or sealant

New York City boasts more than 5,600 rooftop water tanks, vital for delivering water to its towering buildings. Crafted with age-old techniques, these wooden tanks naturally seal the water effectively. Due to pressure limitations in the municipal system, rooftops of buildings taller than six stories are required to have these tanks.